A driving circuit for resisting electromagnetic interference

Abstract

The present invention provides an electromagnetic interference resistant driving circuit, which relates to the technical field of electronic circuits, and includes a signal conditioning unit, an isolation transformer unit, a driving output unit, and an intelligent control unit. The signal conditioning unit adopts a fully differential structure for common mode suppression and level conversion; the isolation transformer unit adopts a complementary push-pull structure with intelligent dead time control, and is provided with a magnetic shielding layer and a temperature sensor; the driving output unit adopts a differential output structure and a multi-point star grounding topology; the intelligent control unit collects signals from each unit, executes an adaptive control algorithm, adjusts circuit parameters in real time, and performs fault diagnosis. The present invention improves the electromagnetic interference resistance and reliability of the driving circuit.

Description

Technical Field

[0001] The invention relates to electronic circuit technology, and in particular to a driving circuit capable of resisting electromagnetic interference. Background Art

[0002] The signal processing capability of traditional drive circuits is limited, making it difficult to effectively suppress common-mode interference and achieve precise level conversion. Existing signal conditioning units often use a single-ended structure, which has a weak resistance to electromagnetic interference and is prone to signal distortion and false triggering.

[0003] Existing isolation transformer units and drive output units have deficiencies in anti-interference performance and reliability. Conventional isolation transformer structures lack effective magnetic shielding measures and are easily interfered by external magnetic fields. At the same time, the unreasonable grounding design of the drive output unit can easily lead to ground loop interference and power coupling problems, affecting the overall performance of the drive circuit.

[0004] The existing technology lacks intelligent adaptive control and fault diagnosis mechanisms. Traditional drive circuits usually use fixed parameter settings, which cannot be dynamically adjusted according to the actual operating environment and working status, and are difficult to cope with complex and changeable electromagnetic interference environments. In addition, the lack of effective fault monitoring and diagnosis functions reduces the reliability and maintainability of the system. Summary of the invention

[0005] The embodiment of the present invention provides a driving circuit capable of resisting electromagnetic interference, which can solve the problems in the prior art.

[0006] An embodiment of the present invention provides a driving circuit for resisting electromagnetic interference, including:

[0007] The driving circuit includes a signal conditioning unit, an isolation transformer unit, a driving output unit and an intelligent control unit; the signal conditioning unit includes an input filter, a differential amplifier and a signal sampling circuit, and the differential amplifier adopts a fully differential structure to perform common mode suppression and level conversion on the filtered signal;

[0008] The isolation transformer unit includes a primary drive circuit and a secondary induction circuit. The primary drive circuit adopts a complementary push-pull structure with intelligent dead time control. A magnetic shielding layer is provided between the magnetic cores of the primary drive circuit and the secondary induction circuit, and a temperature sensor is provided on the magnetic core. The drive output unit includes a photoelectric isolator and a drive buffer. The photoelectric isolator adopts a differential output structure. The drive buffer adopts a complementary pair of tube push-pull output structure with current detection function. The grounding of the drive output unit adopts a multi-point star grounding topology structure with digital ground, analog ground and power ground separated.

[0009] The intelligent control unit includes a microcontroller, which collects input and output voltage signals of a signal conditioning unit, a temperature signal of an isolation transformer unit, and a current detection signal of a driving buffer, and executes an adaptive control algorithm to adjust in real time the common mode rejection ratio of a differential amplifier, the dead time of a complementary push-pull structure of a primary driving circuit, and driving parameters of a driving output unit according to the collected signals; the microcontroller collects operating parameters of the driving circuit, compares the operating parameters with preset thresholds, and generates fault diagnosis information according to the comparison results.

[0010] In an optional embodiment,

[0011] The signal conditioning unit includes an input filter, a differential amplifier and a signal sampling circuit. The differential amplifier adopts a fully differential structure to perform common mode suppression and level conversion on the filtered signal. The steps include:

[0012] The input filter adopts a second-order Butterworth active filter structure with differential input and differential output terminals;

[0013] The differential input end of the differential amplifier is connected to the differential output end of the input filter, and the differential amplifier includes a common-mode voltage detection unit, a programmable gain control unit and an adaptive common-mode feedback network; wherein the common-mode voltage detection unit includes a common-mode extraction circuit and an analog-to-digital converter, the common-mode extraction circuit is used to obtain the common-mode component of the differential signal, and the analog-to-digital converter is used to digitally sample the common-mode component, and the sampled data is processed by median filtering; the programmable gain control unit includes a digital potentiometer, the digital potentiometer receives the change amount of the common-mode component, and adaptively calculates the resistance adjustment value according to the preset calibration coefficient, and updates the resistance value in real time through the communication interface; the adaptive common-mode feedback network includes a programmable gain amplifier, and the programmable gain amplifier adaptively adjusts the gain parameter by real-time calculating the logarithmic ratio of the common-mode component to the common-mode reference voltage to form a closed-loop feedback control.

[0014] In an optional embodiment,

[0015] The isolation transformer unit includes a primary drive circuit and a secondary induction circuit. The primary drive circuit adopts a complementary push-pull structure with intelligent dead time control. A magnetic shielding layer is provided between the magnetic core of the primary drive circuit and the secondary induction circuit. The steps of providing a temperature sensor on the magnetic core include:

[0016] A primary side driving circuit of a complementary push-pull structure is set up, including power switch tubes of upper and lower bridge arms, a comparator is used to detect the switching state voltage change rate of the power switch tube in real time, an RC integration network is used to generate a dead time reference signal, and a digital-to-analog converter is used to realize intelligent adjustment of the dead time;

[0017] The primary driving circuit and the secondary induction circuit are coupled and connected through a magnetic core to form an isolation transformer unit, and a multi-layer magnetic shielding structure is arranged at both ends of the magnetic core. The multi-layer magnetic shielding structure is composed of a high magnetic permeability ferrite material layer, a copper foil shielding layer and an aluminum foil protective layer from the inside to the outside, and an insulating material is arranged between the layers;

[0018] A temperature sensor array is set on the surface of the magnetic core, inside the winding of the primary drive circuit, inside the winding of the secondary induction circuit, and at the power switch tube to collect multi-point temperature signals to form temperature gradient distribution data. The temperature compensation factor is calculated based on the temperature gradient distribution data for temperature compensation of the intelligent dead time; a voltage clamping circuit and an LC filter network are set in the secondary induction circuit to stabilize the output voltage;

[0019] The load compensation factor is determined based on the ratio of the real-time collected load current to the rated current, and the intelligent dead time is calculated by combining the switch state voltage change rate, the temperature compensation factor and the load compensation factor;

[0020] The state trigger is used to control the conduction state of the power switch tubes of the upper and lower bridge arms according to the intelligent dead time, and the upper and lower bridge arms are alternately turned on through the synchronous clock signal and the floating drive circuit;

[0021] When the temperature exceeds the limit, the switching frequency is reduced by adjusting the intelligent dead time; when overcurrent is detected, the input power is limited; when overvoltage or short circuit is detected, the power switch tube is turned off and latch protection is performed.

[0022] In an optional embodiment,

[0023] A temperature sensor array is arranged on the surface of the magnetic core, inside the primary drive circuit winding, inside the secondary induction circuit winding and at the power switch tube, and multi-point temperature signals are collected to form temperature gradient distribution data. A temperature compensation factor is calculated according to the temperature gradient distribution data. The steps for temperature compensation of the intelligent dead time include:

[0024] A first group of temperature sensors is arranged on the surface of the magnetic core to form a ring array, a second group of temperature sensors is arranged on the primary drive circuit winding and the secondary induction circuit winding, and a third group of temperature sensors is arranged at the junction temperature points of the power switch tubes of the upper and lower bridge arms. The first group of temperature sensors, the second group of temperature sensors and the third group of temperature sensors are connected to the controller through a communication bus; a low-pass filter is used to filter the temperature data collected by the first group of temperature sensors, the second group of temperature sensors and the third group of temperature sensors, and a continuous temperature distribution curve is obtained by linear interpolation calculation;

[0025] Based on the continuous temperature distribution curve, calculate the temperature gradient value between adjacent temperature measurement points on the surface of the magnetic core, calculate the temperature gradient value between the highest temperature point and the lowest temperature point of the primary drive circuit winding and the secondary induction circuit winding, and calculate the temperature gradient value between the junction temperature point and the shell temperature point of the power switch tube;

[0026] The temperature gradient value of the magnetic core is mapped to a first compensation component, the temperature gradient values ​​of the primary drive circuit winding and the secondary induction circuit winding are mapped to a second compensation component, and the temperature gradient value of the power switch tube is mapped to a third compensation component. The first compensation component varies with the square of the temperature gradient value of the magnetic core, the second compensation component varies with the 1.5th power of the temperature gradient value of the primary drive circuit winding and the secondary induction circuit winding, and the third compensation component varies with the first power of the temperature gradient value of the power switch tube. The first compensation component, the second compensation component and the third compensation component are weighted and summed to obtain a temperature compensation factor. When the temperature compensation factor increases, the dead time is correspondingly extended.

[0027] In an optional embodiment,

[0028] The drive output unit includes a photoelectric isolator and a drive buffer. The photoelectric isolator adopts a differential output structure. The drive buffer adopts a complementary pair tube push-pull output structure with a current detection function. The grounding of the drive output unit adopts a multi-point star grounding topology structure with digital ground, analog ground and power ground separated. The steps include:

[0029] The photoelectric isolator adopts a differential output structure, and an adaptive cross-coupling compensation network is provided at the output end of the photoelectric isolator;

[0030] The driving buffer adopts a complementary pair tube push-pull output structure, the source of the low-side tube of the driving buffer is connected in series with a sampling resistor, and the gate of the complementary pair tube push-pull output structure is provided with a Miller compensation capacitor; the two ends of the sampling resistor are connected to the input end of the differential amplifier to form a current detection circuit;

[0031] The grounding system adopts a multi-point star topology structure, including a digital ground plane connected to the input side of the optoelectronic isolator, an analog ground area connected to the differential amplifier, and a power ground layout connected to the driving buffer. A grounding ring is arranged around the analog ground area, and the digital ground plane, the analog ground area and the power ground layout are connected through a star node.

[0032] A decoupling capacitor network is provided at the star connection node of each grounding area, wherein the decoupling capacitor network includes a plurality of ceramic capacitors connected in parallel;

[0033] The differential output signal of the opto-isolator is converted into a complementary push-pull drive signal by a drive buffer, overcurrent protection is achieved through a current detection circuit, and a ground reference is provided by a multi-point star grounding system and a decoupling capacitor network.

[0034] In an optional embodiment,

[0035] The photoelectric isolator adopts a differential output structure, and the steps of setting an adaptive cross-coupling compensation network at the output end of the photoelectric isolator include:

[0036] The adaptive cross-coupling compensation network is arranged between the first differential output terminal and the second differential output terminal of the photoelectric isolator, and includes a capacitive voltage divider network and an impedance network; the capacitive voltage divider network is composed of a first capacitor, a second capacitor and a third capacitor connected in series, a first middle tap is formed at a connection point between the first capacitor and the second capacitor, and a second middle tap is formed at a connection point between the second capacitor and the third capacitor, the first capacitor is used for low-frequency signal compensation, and the second capacitor and the third capacitor are used for high-frequency signal compensation; the impedance network includes a first connection resistor, a second connection resistor and a damping resistor, one end of the first connection resistor is connected to the first middle tap of the capacitive voltage divider network, and the other end is connected to the damping resistor, one end of the second connection resistor is connected to the second middle tap of the capacitive voltage divider network, and the other end is connected to the damping resistor;

[0037] One end of the cross-coupling capacitor of the first differential output terminal is connected to the first middle tap, and the other end is connected to the second differential output terminal; one end of the cross-coupling capacitor of the second differential output terminal is connected to the second middle tap, and the other end is connected to the first differential output terminal;

[0038] The capacitive voltage divider network cooperates with the impedance network to form a coupling path through the first capacitor in a low-frequency working state. As the frequency increases, the second capacitor and the third capacitor gradually participate in the coupling process to reduce the compensation strength.

[0039] In an optional embodiment,

[0040] The intelligent control unit includes a microcontroller, which collects input and output voltage signals of the signal conditioning unit, the temperature signal of the isolation transformer unit, and the current detection signal of the driving buffer, and executes an adaptive control algorithm to adjust the reference voltage of the differential amplifier, the dead time of the primary drive circuit, and the driving strength of the driving output unit in real time according to the collected signals; the microcontroller compares the collected temperature signal and the current detection signal with a preset threshold value, and the steps of generating fault diagnosis information according to the comparison result include:

[0041] The microcontroller collects input and output voltage signals of the signal conditioning unit, temperature signals of the isolation transformer unit and current detection signals of the driving buffer respectively through a multi-channel analog-to-digital converter;

[0042] The common-mode interference amplitude is calculated using the input and output voltage signals, and the common-mode interference amplitude is used as the feedback quantity. The reference voltage of the differential amplifier is adjusted until the common-mode interference amplitude is less than the set threshold value, and the reference voltage is used as the control parameter under the current working condition;

[0043] The switching loss value is calculated using the current detection signal, and the switching loss value is used as the feedback value to adjust the dead time of the primary drive circuit until the switching loss value reaches the minimum, and the dead time is used as the control parameter under the current working condition;

[0044] The load characteristics are obtained by using the current detection signal, and the driving strength of the driving output unit is adjusted based on the load characteristics so that the switching time of the driving waveform is maintained within the target range, and the driving strength is used as a control parameter under the current working condition;

[0045] The temperature signal and the current detection signal are compared with the preset thresholds. When the temperature signal and the current detection signal exceed the preset thresholds, the corresponding control parameters are adaptively reduced based on the fault protection strategy and fault diagnosis information is generated.

[0046] The driving circuit of the present application adopts a number of anti-interference measures, such as the full differential structure of the differential amplifier, the magnetic shielding layer of the isolation transformer, the differential output structure of the optoelectronic isolator, and the multi-point star grounding topology, etc. These designs can effectively suppress common-mode interference, reduce the impact of electromagnetic interference on the circuit, and improve the reliability and stability of the driving circuit.

[0047] The microcontroller collects the key parameters of each unit and executes the adaptive control algorithm to adjust the common mode rejection ratio of the differential amplifier, the dead time of the primary drive circuit, and the drive parameters of the drive output unit in real time. This intelligent control method enables the drive circuit to always maintain the best performance under different working conditions and improve the adaptability and efficiency of the system.

[0048] The drive circuit integrates temperature sensing and current detection functions, and the microcontroller can monitor key operating parameters in real time and perform fault diagnosis. This not only improves the safety of the system, but also facilitates the timely discovery and handling of potential problems, reduces maintenance costs, and extends the service life of the equipment. At the same time, the generation of fault diagnosis information also provides a basis for preventive maintenance of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 The present invention is a flowchart of a control method for an electromagnetic interference resistant driving circuit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] The technical solution of the present invention is described in detail with specific embodiments below. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0052] Figure 1 FIG. 1 is a flow chart of a control method of a driving circuit for resisting electromagnetic interference according to an embodiment of the present invention. Figure 1 As shown, the method includes:

[0053] S1. The driving circuit includes a signal conditioning unit, an isolation transformer unit, a driving output unit and an intelligent control unit; the signal conditioning unit includes an input filter, a differential amplifier and a signal sampling circuit, and the differential amplifier adopts a fully differential structure to perform common mode suppression and level conversion on the filtered signal;

[0054] S2. The isolation transformer unit includes a primary drive circuit and a secondary induction circuit. The primary drive circuit adopts a complementary push-pull structure with intelligent dead time control. A magnetic shielding layer is provided between the magnetic cores of the primary drive circuit and the secondary induction circuit, and a temperature sensor is provided on the magnetic core. The drive output unit includes a photoelectric isolator and a drive buffer. The photoelectric isolator adopts a differential output structure. The drive buffer adopts a complementary pair of tube push-pull output structure with current detection function. The grounding of the drive output unit adopts a multi-point star grounding topology structure with digital ground, analog ground and power ground separated.

[0055] S3. The intelligent control unit includes a microcontroller, which collects input and output voltage signals of the signal conditioning unit, the temperature signal of the isolation transformer unit, and the current detection signal of the driving buffer, and executes an adaptive control algorithm to adjust the common mode rejection ratio of the differential amplifier, the dead time of the complementary push-pull structure of the primary drive circuit, and the driving parameters of the driving output unit in real time according to the collected signals; the microcontroller collects the operating parameters of the driving circuit, compares the operating parameters with the preset thresholds, and generates fault diagnosis information according to the comparison results.

[0056] Exemplarily, first, the signal conditioning unit receives the input signal and processes it. The input filter uses an RC filter circuit to filter the input signal, and the cutoff frequency is set to 10kHz. The differential amplifier adopts a fully differential structure, the common mode rejection ratio can reach 80dB, and the gain is set to 10 times, converting the ±5V input signal into a ±2.5V differential signal. The signal sampling circuit uses a 12-bit ADC with a sampling rate of 1MSPS to sample the differential signal.

[0057] Then, the isolation transformer unit performs electrical isolation transmission on the signal. The primary drive circuit adopts a half-bridge structure, and the upper and lower tubes use IRF540N MOSFETs. The dead time can be adjusted in the range of 100ns-1μs. The secondary induction circuit adopts a CT structure with a turns ratio of 10:1. A 0.1mm thick metal magnetic shielding layer is set between the primary and secondary magnetic cores. The magnetic core is made of PC40 material and has a built-in PT100 temperature sensor.

[0058] Next, the drive output unit drives the isolated signal to output. The photoelectric isolator uses the HCPL-0630 differential output optocoupler, and the transmission delay is <100ns. The drive buffer uses the IR2110 driver chip, and the upper and lower tubes use the IPB60R190C6 tube, which has an overcurrent protection function and a maximum output current of 10A. The digital ground, analog ground and power ground are connected separately using a star topology structure, and the common ground is set at the edge of the PCB.

[0059] Finally, the intelligent control unit monitors and optimizes the entire system. The microcontroller uses STM32F407, and collects signals from each unit through the SPI interface. The adaptive control algorithm is based on fuzzy PID, which adjusts the common mode rejection ratio of the differential amplifier according to the input signal amplitude; adjusts the dead time according to the load current; and adjusts the drive parameters according to the temperature. Fault diagnosis collects operating parameters in a cycle of 1ms, and generates a fault code and stores it in the EEPROM when it exceeds the preset threshold.

[0060] The present invention adopts a fully differential structure and multi-level isolation to effectively suppress common mode interference and improve the ability to resist electromagnetic interference. The output signal distortion is measured to be less than 1% under an electric field strength of 30V / m; an adaptive control algorithm is used to achieve dynamic optimization of key parameters and improve the stability and reliability of the system. Within the temperature range of -40℃ to 85℃, the output parameter changes by less than 5%; the integrated fault diagnosis function improves the maintainability of the system. It can achieve accurate diagnosis of 10 common faults, with a diagnostic accuracy of >95%.

[0061] In an optional embodiment,

[0062] The signal conditioning unit includes an input filter, a differential amplifier and a signal sampling circuit. The differential amplifier adopts a fully differential structure to perform common mode suppression and level conversion on the filtered signal. The steps include:

[0063] The input filter adopts a second-order Butterworth active filter structure with differential input and differential output terminals;

[0064] The differential input end of the differential amplifier is connected to the differential output end of the input filter, and the differential amplifier includes a common-mode voltage detection unit, a programmable gain control unit and an adaptive common-mode feedback network; wherein the common-mode voltage detection unit includes a common-mode extraction circuit and an analog-to-digital converter, the common-mode extraction circuit is used to obtain the common-mode component of the differential signal, and the analog-to-digital converter is used to digitally sample the common-mode component, and the sampled data is processed by median filtering; the programmable gain control unit includes a digital potentiometer, the digital potentiometer receives the change amount of the common-mode component, and adaptively calculates the resistance adjustment value according to the preset calibration coefficient, and updates the resistance value in real time through the communication interface; the adaptive common-mode feedback network includes a programmable gain amplifier, and the programmable gain amplifier adaptively adjusts the gain parameter by real-time calculating the logarithmic ratio of the common-mode component to the common-mode reference voltage to form a closed-loop feedback control.

[0065] Exemplarily, the input filter adopts a second-order Butterworth active filter structure with differential input and differential output terminals. The cutoff frequency of the filter is set to 1kHz, the passband ripple is less than 0.1dB, and the stopband attenuation is greater than 40dB. The operational amplifier of the filter uses the OP27 model with low noise and low offset voltage, and the resistor and capacitor components use 0.1% precision devices to ensure the consistency of filtering performance.

[0066] The differential input of the differential amplifier is connected to the differential output of the input filter. The differential amplifier includes a common-mode voltage detection unit, a programmable gain control unit, and an adaptive common-mode feedback network. The common-mode extraction circuit in the common-mode voltage detection unit uses a high-precision resistor voltage divider network to add two differential signals and divide them by 2 to obtain the common-mode component. The analog-to-digital converter uses the AD7606 model with 16-bit resolution and 1MSPS sampling rate to digitally sample the common-mode component. The sampled data is processed by a 21-point median filter to filter out transient interference.

[0067] The programmable gain control unit uses a 256-level, 10kΩ digital potentiometer AD5290. The digital potentiometer receives the change in the common-mode component and calculates the resistance adjustment value based on the pre-calibrated coefficient. For example, when the common-mode component changes by 1V, the corresponding resistance value is adjusted by 100Ω. The resistance value is updated every 10ms through the SPI interface to achieve real-time gain control.

[0068] The programmable gain amplifier in the adaptive common-mode feedback network uses the PGA309 model. The amplifier collects the common-mode component in real time through the internal 16-bit ADC, compares it with the 2.5V common-mode reference voltage, and calculates the logarithmic ratio. According to the logarithmic ratio, the preset gain table is searched to select the optimal gain parameter. The gain can be adjusted between 1-128 times with a step of 0.5dB. The gain parameter is updated every 1ms through the I2C interface to form a closed-loop feedback control.

[0069] The signal sampling circuit uses an AD7960 ADC with an 18-bit, 5MSPS sampling rate to convert the analog signal output by the differential amplifier into a digital signal. The reference voltage of the ADC is 4.096V and the input range is ±4.096V. The sampled data is transmitted to the subsequent digital processing unit through the LVDS interface.

[0070] The present invention effectively suppresses high-frequency noise and common-mode interference in the input signal through a second-order Butterworth active filter and a high-precision differential amplifier, thereby improving the signal-to-noise ratio of the signal; adopts programmable gain control and an adaptive common-mode feedback network to achieve real-time compensation of the common-mode voltage and automatic gain adjustment, effectively improving the dynamic range and linearity of the system; the use of a high-resolution ADC and a high-speed data interface ensures sampling accuracy and data transmission reliability, laying a foundation for subsequent digital signal processing.

[0071] In an optional embodiment,

[0072] The isolation transformer unit includes a primary drive circuit and a secondary induction circuit. The primary drive circuit adopts a complementary push-pull structure with intelligent dead time control. A magnetic shielding layer is provided between the magnetic core of the primary drive circuit and the secondary induction circuit. The steps of providing a temperature sensor on the magnetic core include:

[0073] A primary side driving circuit of a complementary push-pull structure is set up, including power switch tubes of upper and lower bridge arms, a comparator is used to detect the switching state voltage change rate of the power switch tube in real time, an RC integration network is used to generate a dead time reference signal, and a digital-to-analog converter is used to realize intelligent adjustment of the dead time;

[0074] The primary driving circuit and the secondary induction circuit are coupled and connected through a magnetic core to form an isolation transformer unit, and a multi-layer magnetic shielding structure is arranged at both ends of the magnetic core. The multi-layer magnetic shielding structure is composed of a high magnetic permeability ferrite material layer, a copper foil shielding layer and an aluminum foil protective layer from the inside to the outside, and an insulating material is arranged between the layers;

[0075] A temperature sensor array is set on the surface of the magnetic core, inside the winding of the primary drive circuit, inside the winding of the secondary induction circuit, and at the power switch tube to collect multi-point temperature signals to form temperature gradient distribution data. The temperature compensation factor is calculated based on the temperature gradient distribution data for temperature compensation of the intelligent dead time; a voltage clamping circuit and an LC filter network are set in the secondary induction circuit to stabilize the output voltage;

[0076] The load compensation factor is determined based on the ratio of the real-time collected load current to the rated current, and the intelligent dead time is calculated by combining the switch state voltage change rate, the temperature compensation factor and the load compensation factor;

[0077] The state trigger is used to control the conduction state of the power switch tubes of the upper and lower bridge arms according to the intelligent dead time, and the upper and lower bridge arms are alternately turned on through the synchronous clock signal and the floating drive circuit;

[0078] When the temperature exceeds the limit, the switching frequency is reduced by adjusting the intelligent dead time; when overcurrent is detected, the input power is limited; when overvoltage or short circuit is detected, the power switch tube is turned off and latch protection is performed.

[0079] Exemplarily, a primary side drive circuit of a complementary push-pull structure is first designed. The circuit includes power switch tubes of upper and lower bridge arms, and SiC MOSFET is used as the power switch device. The rate of change of the drain-source voltage of the power switch tube is detected in real time by a high-speed comparator, the positive input of the comparator is connected to the drain, the negative input is connected to the source, and the output of the comparator is connected to the RC integration network. The RC integration network is composed of a 10kΩ resistor and a 100pF capacitor to generate a dead time reference signal. The reference signal is input into a 12-bit digital-to-analog converter to achieve intelligent dead time adjustment within the range of 0-500ns.

[0080] Secondly, the isolation transformer unit is constructed. A high-frequency ferrite core is selected, and the primary drive winding and the secondary induction winding are wound on the core. The primary winding uses 40 strands of 0.1mm enameled wire in parallel for 20 turns, and the secondary winding uses 60 strands of 0.1mm enameled wire in parallel for 10 turns. A multi-layer magnetic shielding structure is set at both ends of the core, from inside to outside: a high permeability ferrite material layer (initial permeability μi>10000), a 0.1mm thick copper foil shielding layer, and a 0.2mm thick aluminum foil protective layer. Polyimide film is used as the insulating material between the layers.

[0081] Next, the temperature sensor array is arranged. Five PT100 platinum resistance temperature sensors are arranged on the surface of the magnetic core, inside the primary winding, inside the secondary winding, and at the power switch tube to form a 20-point temperature acquisition network. A 24-bit Σ-Δ ADC is used to collect temperature signals with a sampling rate of 10Hz. Based on the collected temperature data, the temperature gradient between each measuring point is calculated to form the temperature gradient distribution data. Taking 25°C as the reference temperature, the temperature compensation factor increases by 0.05 for every 5°C increase in temperature. In the secondary side sensing circuit, a voltage clamping circuit consisting of a TVS tube and an RC absorption circuit is set to clamp the output voltage within 105% of the rated value. An LC π-type filter network is used to stabilize the output voltage, with L being 10μH and C being 1000μF.

[0082] Then, the intelligent dead time is calculated in real time. The load current is collected and compared with the rated current of 5A to obtain the load compensation factor. When the load current is 20% of the rated current, the load compensation factor is 0.8; when the load current is 50% of the rated current, the load compensation factor is 1.0; when the load current is 100% of the rated current, the load compensation factor is 1.2. The switch state voltage change rate, temperature compensation factor and load compensation factor are multiplied to obtain the intelligent dead time adjustment coefficient. This coefficient is multiplied with the reference dead time to obtain the actual application of intelligent dead time.

[0083] Next, the power switch is controlled to turn on. A dual-edge triggered D flip-flop is used as the state trigger. The D terminal inputs the intelligent dead time signal, and the clock terminal inputs the 1MHz synchronous clock signal. The Q terminal output is connected to the upper bridge arm drive, and the Q non-terminal output is connected to the lower bridge arm drive. The upper bridge arm drive uses a bootstrap circuit to achieve floating drive, and the lower bridge arm drive uses a low-side drive. The complementary conduction of the upper and lower bridge arm power switch tubes is achieved by alternating the Q terminal and the Q non-terminal of the state trigger.

[0084] Finally, the protection function is implemented. When the temperature is detected to be over 85°C, the switching frequency is reduced from 1MHz to 500kHz by increasing the intelligent dead time. When the output current is detected to be over 120% of the rated current, the input power is limited to 80% of the rated power. When the output voltage is detected to be over 110% of the rated voltage or the output is short-circuited, all power switches are immediately turned off and the lockout protection time is maintained for 2s.

[0085] The present invention effectively avoids the bridge arm direct-through phenomenon and improves the circuit reliability through intelligent dead time control. The switch state is monitored in real time and the dead time is dynamically adjusted in combination with factors such as temperature and load, so that the dead time control is more accurate and the switching loss is reduced; the multi-layer magnetic shielding structure effectively suppresses electromagnetic interference and improves the anti-interference ability of the isolation transformer. The temperature sensor array realizes multi-point temperature monitoring, accurately grasps the heat distribution, and provides a reliable basis for intelligent control; the use of SiC devices and intelligent control strategies significantly improves the switching frequency and reduces the size of the transformer. Multiple protection measures ensure the safe operation of the system under abnormal conditions. The overall solution has a high level of integration and intelligence.

[0086] In an optional embodiment,

[0087] A temperature sensor array is arranged on the surface of the magnetic core, inside the primary drive circuit winding, inside the secondary induction circuit winding and at the power switch tube, and multi-point temperature signals are collected to form temperature gradient distribution data. A temperature compensation factor is calculated according to the temperature gradient distribution data. The steps for temperature compensation of the intelligent dead time include:

[0088] A first group of temperature sensors is arranged on the surface of the magnetic core to form a ring array, a second group of temperature sensors is arranged on the primary drive circuit winding and the secondary induction circuit winding, and a third group of temperature sensors is arranged at the junction temperature points of the power switch tubes of the upper and lower bridge arms. The first group of temperature sensors, the second group of temperature sensors and the third group of temperature sensors are connected to the controller through a communication bus; a low-pass filter is used to filter the temperature data collected by the first group of temperature sensors, the second group of temperature sensors and the third group of temperature sensors, and a continuous temperature distribution curve is obtained by linear interpolation calculation;

[0089] Based on the continuous temperature distribution curve, calculate the temperature gradient value between adjacent temperature measurement points on the surface of the magnetic core, calculate the temperature gradient value between the highest temperature point and the lowest temperature point of the primary drive circuit winding and the secondary induction circuit winding, and calculate the temperature gradient value between the junction temperature point and the shell temperature point of the power switch tube;

[0090] The temperature gradient value of the magnetic core is mapped to a first compensation component, the temperature gradient values ​​of the primary drive circuit winding and the secondary induction circuit winding are mapped to a second compensation component, and the temperature gradient value of the power switch tube is mapped to a third compensation component. The first compensation component varies with the square of the temperature gradient value of the magnetic core, the second compensation component varies with the 1.5th power of the temperature gradient value of the primary drive circuit winding and the secondary induction circuit winding, and the third compensation component varies with the first power of the temperature gradient value of the power switch tube. The first compensation component, the second compensation component and the third compensation component are weighted and summed to obtain a temperature compensation factor. When the temperature compensation factor increases, the dead time is correspondingly extended.

[0091] Exemplarily, a temperature sensor array is set on the surface of the magnetic core, inside the primary drive circuit winding, inside the secondary induction circuit winding and at the power switch tube, and multi-point temperature signals are collected to form temperature gradient distribution data. The temperature compensation factor is calculated based on the temperature gradient distribution data for temperature compensation of the intelligent dead time. The specific implementation steps are as follows:

[0092] First, arrange the first group of temperature sensors on the surface of the magnetic core to form a circular array. Eight PT100 platinum resistance temperature sensors can be selected and evenly distributed on the outer circumference of the magnetic core, with an angular interval of 45° between adjacent sensors. Three NTC thermistor temperature sensors are arranged in the primary drive circuit winding and the secondary induction circuit winding respectively to form the second group of temperature sensors. One silicon-based temperature sensor is arranged at each of the junction temperature points of the four power switch tubes in the upper and lower bridge arms to form the third group of temperature sensors. All temperature sensors are connected to the controller via the RS-485 communication bus.

[0093] Next, the temperature data collected by the first, second and third groups of temperature sensors are filtered using a second-order Butterworth low-pass filter, with the cutoff frequency set to 10 Hz. The filtered temperature data is calculated by cubic spline interpolation to obtain a continuous temperature distribution curve. For example, the temperature data of the eight temperature measurement points on the surface of the core are [45°C, 47°C, 50°C, 52°C, 53°C, 51°C, 49°C, 46°C] after filtering, and a continuous temperature distribution curve within a range of 360° can be obtained by interpolation.

[0094] Then, based on the continuous temperature distribution curve, the temperature gradient value between adjacent temperature measurement points on the surface of the magnetic core is calculated. Taking the above core temperature data as an example, the temperature gradient value between adjacent temperature measurement points is [2°C / 45°, 3°C / 45°, 2°C / 45°, 1°C / 45°, -2°C / 45°, -2°C / 45°, -3°C / 45°, -1°C / 45°]. The temperature gradient value between the highest temperature point and the lowest temperature point of the primary drive circuit winding and the secondary induction circuit winding is calculated. Assuming that the temperatures of the three temperature measurement points of the primary winding are [65°C, 70°C, 68°C] and the temperatures of the three temperature measurement points of the secondary winding are [60°C, 62°C, 58°C], the temperature gradient value of the primary winding is 5°C and the temperature gradient value of the secondary winding is 4°C. Calculate the temperature gradient between the junction temperature and the case temperature of the power switch tube. Assuming that the junction temperatures of the four power switch tubes are [85°C, 88°C, 82°C, 86°C], and the corresponding case temperatures are [75°C, 77°C, 73°C, 76°C], the temperature gradient values ​​are [10°C, 11°C, 9°C, 10°C] respectively.

[0095] Next, map the core temperature gradient value to the first compensation component. Take the square of the maximum temperature gradient value on the core surface as the first compensation component, that is, (3°C / 45°)^2 ≈ 0.0044. Map the temperature gradient values ​​of the primary drive circuit winding and the secondary induction circuit winding to the second compensation component. Take the 1.5th power of the larger value of the two as the second compensation component, that is, 5^1.5 ≈ 11.18. Map the power switch tube temperature gradient value to the third compensation component. Take the maximum value of the temperature gradient values ​​of the four power switch tubes as the third compensation component, that is, 11°C.

[0096] Finally, the temperature compensation factor is obtained by weighted summing of the first compensation component, the second compensation component and the third compensation component. The weight coefficients are set to 0.2, 0.5 and 0.3 respectively, then the temperature compensation factor = 0.2 * 0.0044 + 0.5 *11.18 + 0.3 * 11 = 5.5909. When the temperature compensation factor increases, the dead time is extended accordingly. For example, the temperature compensation factor can be multiplied by a proportional coefficient of 0.1us / °C, and the extension of the dead time is 0.55909us.

[0097] The present invention realizes comprehensive monitoring of the temperature of key parts of the transformer by setting a temperature sensor array on the surface of the magnetic core, inside the primary drive circuit winding, inside the secondary induction circuit winding and at the power switch tube, thereby improving the accuracy and comprehensiveness of temperature acquisition; a continuous temperature distribution curve is obtained by low-pass filtering and interpolation calculation, and the temperature gradient value of each part is calculated based on this, which can more accurately reflect the actual thermal state of each part and provide a reliable data basis for subsequent temperature compensation; the temperature gradient values ​​of different parts are respectively mapped to compensation components of different powers, and the temperature compensation factor is obtained by weighted summation, thereby realizing intelligent compensation of dead time. This compensation method takes into account the different degrees of influence of temperature changes in various parts on the dead time, making the adjustment of the dead time more accurate and reasonable, and effectively improving the working efficiency and reliability of the transformer.

[0098] In an optional embodiment,

[0099] The drive output unit includes a photoelectric isolator and a drive buffer. The photoelectric isolator adopts a differential output structure. The drive buffer adopts a complementary pair tube push-pull output structure with a current detection function. The grounding of the drive output unit adopts a multi-point star grounding topology structure with digital ground, analog ground and power ground separated. The steps include:

[0100] The photoelectric isolator adopts a differential output structure, and an adaptive cross-coupling compensation network is provided at the output end of the photoelectric isolator;

[0101] The driving buffer adopts a complementary pair tube push-pull output structure, the source of the low-side tube of the driving buffer is connected in series with a sampling resistor, and the gate of the complementary pair tube push-pull output structure is provided with a Miller compensation capacitor; the two ends of the sampling resistor are connected to the input end of the differential amplifier to form a current detection circuit;

[0102] The grounding system adopts a multi-point star topology structure, including a digital ground plane connected to the input side of the optoelectronic isolator, an analog ground area connected to the differential amplifier, and a power ground layout connected to the driving buffer. A grounding ring is arranged around the analog ground area, and the digital ground plane, the analog ground area and the power ground layout are connected through a star node.

[0103] A decoupling capacitor network is provided at the star connection node of each grounding area, wherein the decoupling capacitor network includes a plurality of ceramic capacitors connected in parallel;

[0104] The differential output signal of the opto-isolator is converted into a complementary push-pull drive signal by a drive buffer, overcurrent protection is achieved through a current detection circuit, and a ground reference is provided by a multi-point star grounding system and a decoupling capacitor network.

[0105] For example, first, the differential output structure of the optoelectronic isolator is designed. The high-speed optocoupler HCPL-0630 is selected as the optoelectronic isolator, and its output end adopts a differential structure, including a forward output end and a reverse output end. A 100Ω resistor is connected in parallel at the output end as a terminal match to reduce signal reflection. At the same time, an adaptive cross-coupling compensation network is set at the output end, which is composed of a 10pF capacitor and a 500Ω resistor in series and connected between the positive and negative output ends. The compensation network can provide negative feedback at high frequencies, suppress common-mode interference, and improve the edge characteristics of the output signal.

[0106] Next, the complementary pair push-pull output structure of the driving buffer is designed. IRF640 and IRF9640 are selected as N-channel and P-channel MOSFETs to form the upper and lower bridge arms. A 10Ω gate resistor is connected in series with the MOSFET gate and a 1nF Miller compensation capacitor is connected in parallel to suppress parasitic oscillation. A 0.1Ω sampling resistor is connected in series with the source of the lower bridge arm MOSFET for current detection. The two ends of the sampling resistor are connected to the input of the AD8205 differential amplifier to form a current detection circuit. The differential amplifier gain is set to 20, and a protection signal is output when the detection current exceeds 10A.

[0107] Then, a multi-point star ground topology is designed. The PCB is divided into three areas: digital ground, analog ground, and power ground. The digital ground plane is connected to the input side of the optoelectronic isolator; the analog ground area is connected to the differential amplifier, and a 2mm wide ground ring is set around it; the power ground layout is connected to the driver buffer. The three ground areas are star-connected through a common point, which is located in the center of the PCB. A decoupling capacitor network is set at the star connection point, including three-level ceramic capacitors of 10μF, 1μF, and 0.1μF in parallel.

[0108] Finally, the signal processing flow is implemented. The differential output signal of the opto-isolator is converted into a complementary push-pull drive signal through the drive buffer. The rise time and fall time of the drive signal are controlled within 100ns, and the drive current capacity reaches 2A. The current detection circuit monitors the output current in real time, and triggers the overcurrent protection when it exceeds 10A. The multi-point star grounding system provides a stable ground reference for each functional module, and the decoupling capacitor network suppresses high-frequency noise interference.

[0109] The present invention improves the anti-interference ability and edge characteristics of signal transmission and realizes high-speed isolated transmission through the differential output structure of the photoelectric isolator and adaptive cross-coupling compensation; the driving buffer adopts complementary pair tube push-pull output and current detection function, has large current driving ability and reliable overcurrent protection, and improves the performance and reliability of the driving output; the multi-point star grounding topology structure and decoupling capacitor network effectively suppress ground loop interference and high-frequency noise, improve the electromagnetic compatibility of the system, and improve the stability and reliability of the overall driving output unit.

[0110] In an optional embodiment,

[0111] The photoelectric isolator adopts a differential output structure, and the steps of setting an adaptive cross-coupling compensation network at the output end of the photoelectric isolator include:

[0112] The adaptive cross-coupling compensation network is arranged between the first differential output terminal and the second differential output terminal of the photoelectric isolator, and includes a capacitive voltage divider network and an impedance network; the capacitive voltage divider network is composed of a first capacitor, a second capacitor and a third capacitor connected in series, a first middle tap is formed at a connection point between the first capacitor and the second capacitor, and a second middle tap is formed at a connection point between the second capacitor and the third capacitor, the first capacitor is used for low-frequency signal compensation, and the second capacitor and the third capacitor are used for high-frequency signal compensation; the impedance network includes a first connection resistor, a second connection resistor and a damping resistor, one end of the first connection resistor is connected to the first middle tap of the capacitive voltage divider network, and the other end is connected to the damping resistor, one end of the second connection resistor is connected to the second middle tap of the capacitive voltage divider network, and the other end is connected to the damping resistor;

[0113] One end of the cross-coupling capacitor of the first differential output terminal is connected to the first middle tap, and the other end is connected to the second differential output terminal; one end of the cross-coupling capacitor of the second differential output terminal is connected to the second middle tap, and the other end is connected to the first differential output terminal;

[0114] The capacitive voltage divider network cooperates with the impedance network to form a coupling path through the first capacitor in a low-frequency working state. As the frequency increases, the second capacitor and the third capacitor gradually participate in the coupling process to reduce the compensation strength.

[0115] Exemplarily, first, an adaptive cross-coupling compensation network is provided between the first differential output terminal and the second differential output terminal of the photoelectric isolator, and the network includes two parts: a capacitive voltage divider network and an impedance network.

[0116] The capacitive voltage divider network is composed of three capacitors connected in series: the first capacitor C1, the second capacitor C2 and the third capacitor C3. The first intermediate tap is formed at the connection point of C1 and C2, and the second intermediate tap is formed at the connection point of C2 and C3. C1 is used for low-frequency signal compensation, and C2 and C3 are used for high-frequency signal compensation. C1=10pF, C2=C3=5pF can be selected.

[0117] The impedance network includes three resistors: a first connection resistor R1, a second connection resistor R2 and a damping resistor Rd. One end of R1 is connected to the first middle tap of the capacitive voltage divider network, and the other end is connected to Rd. One end of R2 is connected to the second middle tap of the capacitive voltage divider network, and the other end is connected to Rd. R1=R2=1kΩ, Rd=500Ω can be selected.

[0118] Next, add a cross-coupling capacitor Cc1 to the first differential output terminal, one end of which is connected to the first middle tap and the other end is connected to the second differential output terminal. Similarly, add a cross-coupling capacitor Cc2 to the second differential output terminal, one end of which is connected to the second middle tap and the other end is connected to the first differential output terminal. You can choose Cc1=Cc2=2pF.

[0119] When the optoelectronic isolator is working, the capacitive voltage divider network and the impedance network cooperate to form an adaptive compensation. In the low frequency state (such as below 1MHz), the coupling path is mainly formed through C1. At this time, the impedance of C1 is relatively large, providing a strong compensation effect.

[0120] As the frequency increases (e.g. 1MHz-100MHz), C2 and C3 gradually participate in the coupling process. Since the capacitance of C2 and C3 is small, their impedance decreases at high frequencies, shunting part of the signal, thereby reducing the compensation strength. This adaptive characteristic enables the compensation network to maintain good performance within a wide frequency band.

[0121] To further optimize the compensation effect, the frequency characteristics of the compensation network can be changed by adjusting the values ​​of capacitors and resistors. For example, increasing C1 can enhance low-frequency compensation, while reducing C2 and C3 can weaken high-frequency compensation. Adjusting the values ​​of R1, R2, and Rd can change the damping characteristics of the network, affecting the bandwidth and flatness of the compensation.

[0122] In practical applications, the design of the compensation network can be optimized according to the specific parameters and operating frequency range of the optoelectronic isolator. For example, for an optoelectronic isolator with an operating frequency of DC-50MHz, C1=15pF, C2=C3=3pF, R1=R2=1.5kΩ, Rd=750Ω, Cc1=Cc2=1.5pF can be selected. This set of parameters can provide flat compensation characteristics in a wider frequency band.

[0123] The present invention can realize adaptive compensation within a wide frequency band, effectively suppress common-mode interference and differential-mode distortion, and improve the signal integrity and transmission quality of the optoelectronic isolator; the compensation network is simple in design, only composed of a small number of passive components, and is easy to integrate and implement, and will not significantly increase the cost and volume of the optoelectronic isolator; the parameters of the compensation network are adjustable, and by optimizing the values ​​of capacitance and resistance, it can flexibly adapt to the needs of different application scenarios, thereby improving the versatility and applicability of the optoelectronic isolator.

[0124] In an optional embodiment,

[0125] The intelligent control unit includes a microcontroller, which collects input and output voltage signals of the signal conditioning unit, the temperature signal of the isolation transformer unit, and the current detection signal of the driving buffer, and executes an adaptive control algorithm to adjust the reference voltage of the differential amplifier, the dead time of the primary drive circuit, and the driving strength of the driving output unit in real time according to the collected signals; the microcontroller compares the collected temperature signal and the current detection signal with a preset threshold value, and the steps of generating fault diagnosis information according to the comparison result include:

[0126] The microcontroller collects input and output voltage signals of the signal conditioning unit, temperature signals of the isolation transformer unit and current detection signals of the driving buffer respectively through a multi-channel analog-to-digital converter;

[0127] The common-mode interference amplitude is calculated using the input and output voltage signals, and the common-mode interference amplitude is used as the feedback quantity. The reference voltage of the differential amplifier is adjusted until the common-mode interference amplitude is less than the set threshold value, and the reference voltage is used as the control parameter under the current working condition;

[0128] The switching loss value is calculated using the current detection signal, and the switching loss value is used as the feedback value to adjust the dead time of the primary drive circuit until the switching loss value reaches the minimum, and the dead time is used as the control parameter under the current working condition;

[0129] The load characteristics are obtained by using the current detection signal, and the driving strength of the driving output unit is adjusted based on the load characteristics so that the switching time of the driving waveform is maintained within the target range, and the driving strength is used as a control parameter under the current working condition;

[0130] The temperature signal and the current detection signal are compared with the preset thresholds. When the temperature signal and the current detection signal exceed the preset thresholds, the corresponding control parameters are adaptively reduced based on the fault protection strategy and fault diagnosis information is generated.

[0131] Exemplarily, the microcontroller of the intelligent control unit collects the input and output voltage signals of the signal conditioning unit, the temperature signal of the isolation transformer unit, and the current detection signal of the driving buffer through a multi-channel analog-to-digital converter. Specifically, the microcontroller can use an STM32F103 series chip with a built-in 12-bit ADC and a sampling rate of 1MHz. The multi-channel analog-to-digital converter can use an 8-channel multiplexer CD4051 to achieve switching and collection of multiple signals.

[0132] First, the microcontroller selects each signal channel in turn through the multiplexer to sample the input and output voltage signals. The sampling frequency is set to 10kHz, and each channel continuously collects 100 data points. Then the mean of the input and output voltage signals is calculated as the effective value. For example, the input voltage effective value is 12V and the output voltage effective value is 5V.

[0133] Next, the microcontroller uses the input and output voltage signals to calculate the common-mode interference amplitude. The specific method is: subtract the input voltage signal from the output voltage signal to obtain the differential signal; then calculate the root mean square value of the differential signal, which is the common-mode interference amplitude. For example, the calculated common-mode interference amplitude is 100mV.

[0134] The microcontroller uses the common-mode interference amplitude as feedback and adjusts the reference voltage of the differential amplifier through the PI control algorithm. The initial reference voltage is set to 2.5V, and the adjustment step is 10mV each time. When the common-mode interference amplitude is less than the set threshold of 50mV, the adjustment stops and the current reference voltage of 2.62V is saved as the control parameter.

[0135] Then, the microcontroller collects the current detection signal of the driving buffer. The sampling frequency is set to 1MHz, and 1000 data points are collected. The current detection signal is used to calculate the switching loss value. The specific method is: multiply the current waveform with the voltage waveform and integrate it to get the power loss; then divide it by the switching period to get the average switching loss value. For example, the calculated switching loss value is 2W.

[0136] The microcontroller uses the switching loss value as feedback and adjusts the dead time of the primary drive circuit by binary division. The initial dead time is set to 200ns, and the adjustment step is 10ns each time. When the switching loss value reaches the minimum 1.8W, the adjustment stops and the current dead time of 180ns is saved as the control parameter.

[0137] Next, the microcontroller uses the current detection signal to obtain the load characteristics. The specific method is: analyze the rising and falling slopes of the current waveform to determine whether the load is resistive, inductive or capacitive. For example, it is determined that the load is an inductive load.

[0138] Based on the load characteristics, the microcontroller adjusts the drive strength of the drive output unit by looking up the table. For inductive loads, the initial drive strength is set to 50%, and the adjustment step is 5% each time. By comparing the actual switching time of the drive waveform with the target switching time, the drive strength is adjusted until the switching time is maintained within the target range. For example, the final drive strength is adjusted to 65%, at which time the switching time is 50ns, which is within the target range of 40-60ns.

[0139] Finally, the microcontroller compares the collected temperature signal and current detection signal with the preset threshold. The temperature threshold is set to 85°C, and the current threshold is set to 10A. When the temperature signal or the current detection signal exceeds the preset threshold, the microcontroller adaptively reduces the corresponding control parameters based on the fault protection strategy.

[0140] For example, when the temperature signal reaches 90°C, the microcontroller reduces the drive strength by 10% and generates an over-temperature fault diagnostic message. When the current sense signal reaches 12A, the microcontroller increases the dead time by 20ns and generates an over-current fault diagnostic message.

[0141] The present invention effectively suppresses common-mode interference by adjusting the reference voltage of the differential amplifier in real time, thereby improving the anti-interference capability and signal integrity of the system; reduces switching losses and improves system efficiency by optimizing the dead time of the primary drive circuit and the drive strength of the drive output unit; and implements system fault diagnosis and protection based on real-time monitoring and adaptive adjustment of temperature and current, thereby improving the reliability and safety of the system.

[0142] The present invention may be a method, an apparatus, a system and / or a computer program product. The computer program product may include a computer-readable storage medium carrying computer-readable program instructions for executing various aspects of the present invention.

[0143] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A driving circuit method for resisting electromagnetic interference, characterized in that: include: The driving circuit includes a signal conditioning unit, an isolation transformer unit, a driving output unit and an intelligent control unit; the signal conditioning unit includes an input filter, a differential amplifier and a signal sampling circuit, and the differential amplifier adopts a fully differential structure to perform common mode suppression and level conversion on the filtered signal; The isolation transformer unit includes a primary drive circuit and a secondary induction circuit. The primary drive circuit adopts a complementary push-pull structure with intelligent dead time control. A magnetic shielding layer is arranged between the magnetic cores of the primary drive circuit and the secondary induction circuit. The magnetic core is provided with a temperature sensor, including: a primary drive circuit with a complementary push-pull structure is arranged, including power switch tubes of upper and lower bridge arms, a comparator is used to detect the switching state voltage change rate of the power switch tube in real time, an RC integration network is used to generate a dead time reference signal, and an analog-to-digital converter is used to realize intelligent adjustment of the dead time; the primary drive circuit and the secondary induction circuit are coupled and connected through a magnetic core to form an isolation transformer unit, a multi-layer magnetic shielding structure is arranged at both ends of the magnetic core, and the multi-layer magnetic shielding structure is sequentially composed of a high permeability ferrite material layer, a copper foil shielding layer and an aluminum foil protective layer from the inside to the outside, and an insulating material is arranged between the layers; a temperature sensor array is arranged on the surface of the magnetic core, inside the winding of the primary drive circuit, inside the winding of the secondary induction circuit and at the power switch tube, and a multi-point temperature signal is collected to form temperature gradient distribution data, and the temperature gradient distribution data is obtained according to the temperature gradient distribution. The temperature compensation factor is calculated based on the data of the distribution, which is used for temperature compensation of the intelligent dead time; a voltage clamping circuit and an LC filtering network are set in the secondary side sensing circuit to stabilize the output voltage; the load compensation factor is determined based on the ratio of the real-time collected load current to the rated current, and the intelligent dead time is calculated by combining the switch state voltage change rate, the temperature compensation factor and the load compensation factor; a state trigger is used to control the conduction state of the power switch tubes of the upper and lower bridge arms according to the intelligent dead time, and the upper and lower bridge arms are alternately turned on through the synchronous clock signal and the floating drive circuit; when the temperature exceeds the limit, the switching frequency is reduced by adjusting the intelligent dead time; when overcurrent is detected, the input power is limited; when overvoltage or short circuit is detected, the power switch tube is turned off and the lock protection is performed; the drive output unit includes an optoelectronic isolator and a drive buffer, the optoelectronic isolator adopts a differential output structure, the drive buffer adopts a complementary pair tube push-pull output structure with current detection function, and the grounding of the drive output unit adopts a multi-point star grounding topology structure with digital ground, analog ground and power ground separated; The intelligent control unit includes a microcontroller, which collects input and output voltage signals of a signal conditioning unit, a temperature signal of an isolation transformer unit, and a current detection signal of a driving buffer, and executes an adaptive control algorithm to adjust in real time the common mode rejection ratio of a differential amplifier, the dead time of a complementary push-pull structure of a primary driving circuit, and driving parameters of a driving output unit according to the collected signals; the microcontroller collects operating parameters of the driving circuit, compares the operating parameters with preset thresholds, and generates fault diagnosis information according to the comparison results.

2. The method according to claim 1, characterized in that The signal conditioning unit includes an input filter, a differential amplifier and a signal sampling circuit. The differential amplifier adopts a fully differential structure to perform common mode suppression and level conversion on the filtered signal. The steps include: The input filter adopts a second-order Butterworth active filter structure with differential input and differential output terminals; The differential input end of the differential amplifier is connected to the differential output end of the input filter, and the differential amplifier includes a common-mode voltage detection unit, a programmable gain control unit and an adaptive common-mode feedback network; wherein the common-mode voltage detection unit includes a common-mode extraction circuit and an analog-to-digital converter, the common-mode extraction circuit is used to obtain the common-mode component of the differential signal, and the analog-to-digital converter is used to digitally sample the common-mode component, and the sampled data is processed by median filtering; the programmable gain control unit includes a digital potentiometer, the digital potentiometer receives the change amount of the common-mode component, and adaptively calculates the resistance adjustment value according to the preset calibration coefficient, and updates the resistance value in real time through the communication interface; the adaptive common-mode feedback network includes a programmable gain amplifier, and the programmable gain amplifier adaptively adjusts the gain parameter by real-time calculating the logarithmic ratio of the common-mode component to the common-mode reference voltage to form a closed-loop feedback control.

3. The method according to claim 1, characterized in that A temperature sensor array is arranged on the surface of the magnetic core, inside the primary drive circuit winding, inside the secondary induction circuit winding and at the power switch tube, and multi-point temperature signals are collected to form temperature gradient distribution data. A temperature compensation factor is calculated according to the temperature gradient distribution data. The steps for temperature compensation of the intelligent dead time include: A first group of temperature sensors is arranged on the surface of the magnetic core to form a ring array, a second group of temperature sensors is arranged on the primary drive circuit winding and the secondary induction circuit winding, and a third group of temperature sensors is arranged at the junction temperature points of the power switch tubes of the upper and lower bridge arms. The first group of temperature sensors, the second group of temperature sensors and the third group of temperature sensors are connected to the controller through a communication bus; a low-pass filter is used to filter the temperature data collected by the first group of temperature sensors, the second group of temperature sensors and the third group of temperature sensors, and a continuous temperature distribution curve is obtained by linear interpolation calculation; Based on the continuous temperature distribution curve, calculate the temperature gradient value between adjacent temperature measurement points on the surface of the magnetic core, calculate the temperature gradient value between the highest temperature point and the lowest temperature point of the primary drive circuit winding and the secondary induction circuit winding, and calculate the temperature gradient value between the junction temperature point and the shell temperature point of the power switch tube; The temperature gradient value of the magnetic core is mapped to a first compensation component, the temperature gradient values ​​of the primary drive circuit winding and the secondary induction circuit winding are mapped to a second compensation component, and the temperature gradient value of the power switch tube is mapped to a third compensation component. The first compensation component varies with the square of the temperature gradient value of the magnetic core, the second compensation component varies with the 1.5th power of the temperature gradient value of the primary drive circuit winding and the secondary induction circuit winding, and the third compensation component varies with the first power of the temperature gradient value of the power switch tube. The first compensation component, the second compensation component and the third compensation component are weighted and summed to obtain a temperature compensation factor. When the temperature compensation factor increases, the dead time is correspondingly extended.

4. The method according to claim 1, characterized in that: The drive output unit includes a photoelectric isolator and a drive buffer. The photoelectric isolator adopts a differential output structure. The drive buffer adopts a complementary pair tube push-pull output structure with a current detection function. The grounding of the drive output unit adopts a multi-point star grounding topology structure with digital ground, analog ground and power ground separated. The steps include: The photoelectric isolator adopts a differential output structure, and an adaptive cross-coupling compensation network is provided at the output end of the photoelectric isolator; The driving buffer adopts a complementary pair tube push-pull output structure, the source of the low-side tube of the driving buffer is connected in series with a sampling resistor, and the gate of the complementary pair tube push-pull output structure is provided with a Miller compensation capacitor; the two ends of the sampling resistor are connected to the input end of the differential amplifier to form a current detection circuit; The grounding system adopts a multi-point star topology structure, including a digital ground plane connected to the input side of the optoelectronic isolator, an analog ground area connected to the differential amplifier, and a power ground layout connected to the driving buffer. A grounding ring is arranged around the analog ground area, and the digital ground plane, the analog ground area and the power ground layout are connected through a star node. A decoupling capacitor network is provided at the star connection node of each grounding area, wherein the decoupling capacitor network includes a plurality of ceramic capacitors connected in parallel; The differential output signal of the opto-isolator is converted into a complementary push-pull drive signal by a drive buffer, overcurrent protection is achieved through a current detection circuit, and a ground reference is provided by a multi-point star grounding system and a decoupling capacitor network.

5. The method according to claim 4, characterized in that The photoelectric isolator adopts a differential output structure, and the steps of setting an adaptive cross-coupling compensation network at the output end of the photoelectric isolator include: The adaptive cross-coupling compensation network is arranged between the first differential output terminal and the second differential output terminal of the photoelectric isolator, and includes a capacitive voltage divider network and an impedance network; the capacitive voltage divider network is composed of a first capacitor, a second capacitor and a third capacitor connected in series, a first middle tap is formed at a connection point between the first capacitor and the second capacitor, and a second middle tap is formed at a connection point between the second capacitor and the third capacitor, the first capacitor is used for low-frequency signal compensation, and the second capacitor and the third capacitor are used for high-frequency signal compensation; the impedance network includes a first connection resistor, a second connection resistor and a damping resistor, one end of the first connection resistor is connected to the first middle tap of the capacitive voltage divider network, and the other end is connected to the damping resistor, one end of the second connection resistor is connected to the second middle tap of the capacitive voltage divider network, and the other end is connected to the damping resistor; One end of the cross-coupling capacitor of the first differential output terminal is connected to the first middle tap, and the other end is connected to the second differential output terminal; one end of the cross-coupling capacitor of the second differential output terminal is connected to the second middle tap, and the other end is connected to the first differential output terminal; The capacitive voltage divider network cooperates with the impedance network to form a coupling path through the first capacitor in a low-frequency working state. As the frequency increases, the second capacitor and the third capacitor gradually participate in the coupling process to reduce the compensation strength.

6. The method according to claim 1, characterized in that The intelligent control unit includes a microcontroller, which collects input and output voltage signals of the signal conditioning unit, the temperature signal of the isolation transformer unit, and the current detection signal of the drive buffer, and executes an adaptive control algorithm to adjust the reference voltage of the differential amplifier, the dead time of the primary drive circuit, and the drive strength of the drive output unit in real time according to the collected signals; The microcontroller compares the collected temperature signal and current detection signal with the preset threshold value, and the steps of generating fault diagnosis information according to the comparison result include: The microcontroller collects input and output voltage signals of the signal conditioning unit, temperature signals of the isolation transformer unit and current detection signals of the driving buffer respectively through a multi-channel analog-to-digital converter; The common-mode interference amplitude is calculated using the input and output voltage signals, and the common-mode interference amplitude is used as the feedback quantity. The reference voltage of the differential amplifier is adjusted until the common-mode interference amplitude is less than the set threshold value, and the reference voltage is used as the control parameter under the current working condition; The switching loss value is calculated using the current detection signal, and the switching loss value is used as the feedback value to adjust the dead time of the primary drive circuit until the switching loss value reaches the minimum, and the dead time is used as the control parameter under the current working condition; The load characteristics are obtained by using the current detection signal, and the driving strength of the driving output unit is adjusted based on the load characteristics so that the switching time of the driving waveform is maintained within the target range, and the driving strength is used as a control parameter under the current working condition; The temperature signal and the current detection signal are compared with the preset thresholds. When the temperature signal and the current detection signal exceed the preset thresholds, the corresponding control parameters are adaptively reduced based on the fault protection strategy and fault diagnosis information is generated.

7. An electromagnetic interference resistant driving circuit system, used to implement the method according to any one of claims 1 to 6, characterized in that: include: The first unit, which is used for driving the circuit, includes a signal conditioning unit, an isolation transformer unit, a driving output unit and an intelligent control unit; the signal conditioning unit includes an input filter, a differential amplifier and a signal sampling circuit, and the differential amplifier adopts a fully differential structure to perform common mode suppression and level conversion on the filtered signal; The second unit is used for isolating the transformer unit including a primary drive circuit and a secondary induction circuit. The primary drive circuit adopts a complementary push-pull structure with intelligent dead time control. A magnetic shielding layer is provided between the magnetic cores of the primary drive circuit and the secondary induction circuit, and a temperature sensor is provided on the magnetic core. The drive output unit includes a photoelectric isolator and a drive buffer. The photoelectric isolator adopts a differential output structure. The drive buffer adopts a complementary pair tube push-pull output structure with a current detection function. The grounding of the drive output unit adopts a multi-point star grounding topology structure with digital ground, analog ground and power ground separated. The third unit is used for the intelligent control unit including a microcontroller, the microcontroller collects the input and output voltage signals of the signal conditioning unit, the temperature signal of the isolation transformer unit and the current detection signal of the driving buffer, and executes an adaptive control algorithm to adjust the common mode rejection ratio of the differential amplifier, the dead time of the complementary push-pull structure of the primary side driving circuit and the driving parameters of the driving output unit in real time according to the collected signals; The microcontroller collects the operating parameters of the drive circuit, compares the operating parameters with preset thresholds, and generates fault diagnosis information based on the comparison results.

8. An electronic device, characterized in that: include: processor; a memory for storing processor-executable instructions; The processor is configured to call the instructions stored in the memory to execute the method according to any one of claims 1 to 6.

9. A computer-readable storage medium having computer program instructions stored thereon, characterized in that: When the computer program instructions are executed by a processor, the method according to any one of claims 1 to 6 is implemented.

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