Gate light coupling current regulation system and method based on multi-target complementary control

Abstract

This invention relates to the field of gate drive control technology, specifically to a gate optocoupler current regulation system and method based on multi-objective complementary control. The method acquires the gate voltage and the voltage across the device during the switching process of a power device, calculates the rate of change of both voltages, and divides the switching process into a gate initial charging stage, a Miller plateau regulation stage, and a conduction establishment stage based on a joint characteristic sequence. Rising, limiting, and decaying drive current envelope functions are configured for different stages, and the envelope function parameters are corrected in real time according to the deviation between the device voltage change rate and the target reference value. Finally, the corrected envelope function is converted into a target drive current sequence to dynamically adjust the output drive current of the gate optocoupler. This invention can adaptively adjust the drive current, effectively suppressing voltage overshoot and electromagnetic interference while improving switching speed, thus enhancing the stability and reliability of the power device drive process.

Description

Technical Field

[0001] This invention relates to the field of gate drive control technology, and more specifically to a gate optocoupler current regulation system and method based on multi-objective complementary control. Background Technology

[0002] Power devices (such as IGBTs and MOSFETs) are widely used in power electronic converters, motor drives, and new energy power generation. Their switching performance directly affects the system's conversion efficiency and electromagnetic compatibility. Optically isolated gate driving methods are widely used in medium- and high-voltage power conversion applications due to their strong electrical isolation and good anti-interference capabilities.

[0003] The switching process of power devices exhibits distinct phases, typically categorized into the initial gate charging phase, the Miller plateau regulation phase, and the turn-on setup phase. The gate drive current requirements differ significantly between these phases: the initial gate charging phase requires a larger drive current to quickly establish the gate voltage; the Miller plateau regulation phase necessitates limiting the drive current to suppress voltage overshoot and electromagnetic interference; and the turn-on setup phase requires appropriately reducing the drive current to avoid power loss due to over-driving.

[0004] However, existing gate optocoupler driving schemes generally adopt a fixed drive current output method, lacking the ability to monitor the gate voltage change rate and the voltage change rate across the device in real time. This makes it impossible to identify the switching stage of the power device and make targeted adjustments. In actual operation, factors such as bus voltage fluctuations, load condition changes, and device junction temperature drift can all cause the device voltage change rate to deviate from expectations. Fixed drive strategies cannot adaptively compensate for this, making it difficult to achieve a dynamic balance between switching speed and electromagnetic interference suppression.

[0005] Therefore, there is an urgent need for a gate optocoupler current control method that can sense the characteristics of the switching stage in real time and adaptively control the drive current according to the device voltage change rate. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing a gate optocoupler current regulation system and method based on multi-objective complementary control.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A gate optocoupler current regulation method based on multi-objective complementary control is applied to the gate optocoupler driving process of power devices. The method includes:

[0009] Obtain the gate voltage and the voltage across the power device during the switching process;

[0010] Calculate the gate voltage change rate based on the gate voltage, and calculate the device voltage change rate based on the voltage across the power device;

[0011] The switching process of the power device is divided into stages based on the gate voltage change rate and the device voltage change rate;

[0012] For each of the different switching stages, a corresponding driving current envelope function is established, and the parameters of the driving current envelope function corresponding to the current switching stage are corrected according to the device voltage change rate.

[0013] The target gate drive current is generated based on the parameter-corrected drive current envelope function, and the output drive current of the gate optocoupler is adjusted according to the target gate drive current.

[0014] The step of calculating the gate voltage change rate based on the gate voltage and calculating the device voltage change rate based on the voltage across the power device includes:

[0015] The gate voltage and the voltage across the power device are continuously sampled at a preset sampling period to obtain the gate voltage sampling sequence and the device voltage sampling sequence.

[0016] The gate voltage change rate is calculated based on the ratio of the gate voltage difference between adjacent sampling times to the preset sampling period.

[0017] The device voltage change rate is calculated based on the ratio of the device voltage difference at adjacent sampling times to the preset sampling period.

[0018] The step-by-step division of the switching process of the power device based on the gate voltage change rate and the device voltage change rate includes:

[0019] The gate voltage change rate and device voltage change rate corresponding to the same sampling time are combined to generate a joint feature vector, and then a joint feature sequence is formed according to the sampling time sequence.

[0020] The joint feature sequence is input into a preset stage state encoding rule to obtain the stage state identifier sequence corresponding to each sampling time.

[0021] The sampling positions where the state identifiers of adjacent sampling times in the stage state identifier sequence change are used as candidate boundary points. Based on the duration of the state before and after the candidate boundary point and the interval between the candidate boundary points, the candidate boundary points are filtered and merged to obtain the stage boundary point sequence.

[0022] The switching process of power devices is divided into stages based on the aforementioned stage boundary point sequence.

[0023] Based on the duration of states before and after the candidate boundary points and the time interval between candidate boundary points, candidate boundary points are screened and merged to obtain a stage boundary point sequence, including:

[0024] For each candidate boundary point, count the number of continuous sampling points of its adjacent state identifiers before and after it to obtain the forward duration and backward duration.

[0025] The interval between adjacent candidate boundary points is calculated based on the preset sampling period and the sampling positions of adjacent candidate boundary points.

[0026] When the forward duration or backward duration is less than the preset minimum duration, the corresponding candidate boundary point is removed.

[0027] When the interval between adjacent candidate boundary points is less than the preset minimum stage interval, the adjacent candidate boundary points are merged.

[0028] The candidate boundary points that are eliminated and merged are determined as the target boundary point sequence.

[0029] The step of dividing the switching process of the power device into stages based on the stage boundary point sequence includes:

[0030] Based on the target boundary point sequence, the switching process of the power device is divided into multiple continuous time intervals;

[0031] For each time series interval, count the number of times each stage status identifier appears within that time series interval, and determine the stage status identifier that appears most frequently as the dominant status identifier for that time series interval.

[0032] Based on the dominant state identifier corresponding to each time interval, a corresponding switching stage label is assigned to each time interval to obtain the stage division result of the power device switching process. The stage division result includes the gate initial charging stage, the Miller plateau regulation stage, and the conduction establishment stage.

[0033] The process of establishing corresponding drive current envelope functions for different switching stages and adjusting the parameters of the drive current envelope function corresponding to the current switching stage based on the device voltage change rate includes:

[0034] Based on the stage division results of the power device switching process, a corresponding drive current envelope function is configured for each switching stage, resulting in a set of stage drive current envelope functions.

[0035] For each switching stage, the corresponding initial function parameters are determined. The initial function parameters include at least one of the current amplitude parameter, the change slope parameter, and the duration parameter.

[0036] Calculate the function parameter correction amount for the current switching phase based on the device voltage change rate at the current sampling time;

[0037] The driving current envelope function corresponding to the current switching stage is updated according to the function parameter correction amount to obtain the target driving current envelope function.

[0038] The step of calculating the function parameter correction amount for the current switching phase based on the device voltage change rate corresponding to the current sampling time includes:

[0039] Obtain the device voltage change rate at the current sampling moment and determine the reference value of the target device voltage change rate at the current switching stage;

[0040] The device voltage change rate deviation value is calculated based on the difference between the device voltage change rate and the reference value of the target device voltage change rate.

[0041] The device voltage change rate deviation value is input into a preset parameter mapping rule to obtain the function parameter correction amount for the current switching stage. The parameter mapping rule is used to establish the correspondence between the device voltage change rate deviation value and the adjustment range of the drive current envelope function parameter.

[0042] Based on the stage division results of the power device switching process, a corresponding drive current envelope function is configured for each switching stage, resulting in a set of stage drive current envelope functions, including:

[0043] For the initial gate charging phase, a monotonically increasing rising drive current envelope function is configured;

[0044] For the Miller platform control phase, a limited-amplitude drive current envelope function is configured;

[0045] For the conduction setup phase, a monotonically decreasing decaying drive current envelope function is configured;

[0046] The drive current envelope functions corresponding to each switching stage are combined in stage order to obtain the stage drive current envelope function set.

[0047] The step of generating a target gate drive current based on the parameter-corrected drive current envelope function, and adjusting the output drive current of the gate optocoupler according to the target gate drive current, includes:

[0048] Based on the target drive current envelope function corresponding to the current switching stage, the target gate drive current value corresponding to each sampling time is calculated according to the sampling time sequence to generate the target drive current sequence.

[0049] The target drive current sequence is converted into a corresponding optocoupler output regulation control quantity;

[0050] The output drive current of the gate optocoupler is dynamically adjusted according to the optocoupler output adjustment control quantity corresponding to each sampling time.

[0051] A gate optocoupler current regulation system based on multi-objective complementary control is provided to implement the aforementioned gate optocoupler current regulation method based on multi-objective complementary control. The system includes a voltage acquisition module, a rate of change calculation module, a stage division module, an envelope function generation module, a parameter correction module, and a drive adjustment module, wherein:

[0052] The voltage acquisition module is used to acquire the gate voltage and the voltage across the power device during the switching process of the power device.

[0053] The rate of change calculation module is used to calculate the gate voltage rate of change based on the gate voltage, and to calculate the device voltage rate of change based on the voltage across the power device.

[0054] The stage division module is used to divide the switching process of the power device into stages based on the gate voltage change rate and the device voltage change rate, and obtain stage division results for different switching stages.

[0055] The envelope function generation module is used to establish corresponding drive current envelope functions for different switching stages, thereby obtaining a set of stage drive current envelope functions.

[0056] The parameter correction module is used to correct the parameters of the drive current envelope function corresponding to the current switching stage according to the device voltage change rate, so as to obtain the target drive current envelope function.

[0057] The drive adjustment module is used to generate a target gate drive current based on the parameter-corrected drive current envelope function, and adjust the output drive current of the gate optocoupler according to the target gate drive current.

[0058] Compared with the prior art, the beneficial effects of the present invention are:

[0059] 1. This invention constructs a joint feature sequence by simultaneously acquiring the gate voltage and the voltage across the power device and calculating the corresponding rate of change to accurately divide the switching process into stages. For the initial gate charging stage, the Miller plateau control stage, and the conduction establishment stage, rising, limiting, and decaying drive current envelope functions are configured respectively. This changes the single control mode of fixed drive current output in the prior art, effectively suppressing voltage overshoot and electromagnetic interference while ensuring rapid gate charging, and reducing the overdrive loss in the conduction establishment stage.

[0060] 2. This invention introduces a device voltage change rate deviation and parameter mapping rule to correct the current amplitude, change slope and duration parameters of the drive current envelope function in real time. This enables the drive current to be adaptively adjusted according to actual operating conditions such as bus voltage fluctuations, load changes and device junction temperature drift. This effectively solves the problem of switching performance degradation under complex operating conditions in existing fixed drive strategies and improves the stability and reliability of the power device drive process. Attached Figure Description

[0061] Other features, objects, and advantages of the invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0062] Figure 1 A schematic flowchart of the gate optocoupler current regulation method based on multi-objective complementary control provided in an embodiment of the present invention;

[0063] Figure 2 This is a schematic diagram of the gate optocoupler current regulation system based on multi-objective complementary control provided in an embodiment of the present invention. Detailed Implementation

[0064] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0065] Example 1

[0066] Please see Figure 1 The present invention provides an embodiment of a gate optocoupler current regulation method based on multi-objective complementary control, applied to the gate optocoupler driving process of power devices. The specific steps of the method are as follows:

[0067] S1: Obtain the gate voltage and the voltage across the power device during the switching process.

[0068] Specifically, during the gate driving process of a power device, changes in the gate voltage directly reflect the injection and release of gate charge, while changes in the voltage across the power device reflect the device's on-state and the establishment of load current. These two aspects exhibit a clear temporal coupling relationship during the switching transient. A rise in the gate voltage typically corresponds to the charging process of the gate charge, while a decrease in the voltage across the device reflects the power device gradually entering the on-state. Therefore, this embodiment simultaneously acquires both the gate voltage and the voltage across the power device to construct fundamental voltage information that simultaneously reflects the gate driving dynamics and the device switching dynamics, providing a raw data foundation for subsequent rate-of-change calculations and stage division.

[0069] In this embodiment, the gate voltage is a transient voltage signal between the gate and source terminals of the power device, which reflects the voltage change characteristics during the gate charge injection process. The voltage across the power device is a transient voltage signal across the main power circuit of the power device, used to characterize the transition process between the device in the off state, transition state, and on state. When the power device performs an on or off operation, both of the above voltage signals will change significantly in a short period of time and exhibit phased dynamic characteristics, such as the initial gate charging stage, the Miller plateau modulation stage, and the conduction establishment stage.

[0070] Furthermore, to ensure the accuracy of subsequent voltage change rate calculations, this embodiment continuously acquires the gate voltage and the voltage across the power device during the switching operation of the power device, enabling the acquisition of a complete voltage change trajectory throughout the entire switching transition process. By recording this voltage change trajectory, voltage timing data reflecting the transient switching behavior of the power device can be generated, where each sampling moment corresponds to a set of gate voltage and device voltage values.

[0071] Furthermore, by simultaneously acquiring the gate voltage and the voltage across the device, a joint feature sequence can be constructed in subsequent processing, enabling collaborative analysis of drive-side and power-side information during the switching process of the power device. Specifically, the gate voltage reflects the charge control behavior on the drive side, while the voltage across the device reflects the energy transfer process in the power loop.

[0072] The gate voltage and the voltage across the power device obtained in the above manner constitute the original data source for calculating the gate voltage change rate and the device voltage change rate in subsequent steps. This enables the method of this application to provide a stable and continuous data basis for the stage identification of the power device switching process and the regulation of the drive current while maintaining the integrity of the switching dynamic information.

[0073] S2: Calculate the gate voltage change rate based on the gate voltage, and calculate the device voltage change rate based on the voltage across the power device.

[0074] Specifically, the gate voltage and the voltage across the device exhibit significant transient changes. Gate voltage changes reflect the gate charge injection rate, while voltage changes across the device reflect the energy transfer rate when the power device is turned on or off. Simply relying on the absolute value of the voltage is insufficient to characterize the transient dynamic changes of switching. The voltage change rate directly reflects the speed of voltage change per unit time, revealing key dynamic characteristics of power device switching. Therefore, this embodiment calculates the change rate of the gate voltage and the voltage across the power device, converting the original voltage timing signal into a dynamic characteristic quantity reflecting the transient change rate, providing a more sensitive and stable characteristic basis for dividing the switching stages.

[0075] In this embodiment, the gate voltage and the voltage across the power device are continuously sampled at a preset sampling period to form a corresponding voltage sampling sequence. The preset sampling period can be set according to the switching speed of the power device to ensure that sufficiently dense voltage change information is captured during the switching transients, fully reflecting the dynamic change trajectory of the voltage signal, and obtaining the gate and device voltage sampling sequence. Each sampling moment corresponds to a voltage sample value, and the sampling interval in the time dimension is consistent.

[0076] Furthermore, after obtaining the voltage sampling sequence, the ratio of the voltage difference between adjacent sampling moments to the preset sampling period is calculated to obtain the voltage change rate at the corresponding moment. The gate voltage change rate is calculated by using the ratio of the gate voltage difference between two adjacent sampling moments to the sampling time interval to obtain the gate voltage change rate per unit time; the device voltage change rate is calculated by using the ratio of the voltage difference across the device between two adjacent sampling moments to the sampling time interval to obtain the voltage change rate across the power device per unit time.

[0077] Furthermore, during the turn-on process of the power device, the gate voltage change rate is large and positive during the initial gate charging stage, decreases and tends to stabilize during the Miller plateau control stage, and changes again during the conduction establishment stage. The voltage change rate across the device terminals shows a significant negative change during the Miller plateau control stage, reflecting the rapid decrease of the device voltage from the bus voltage to the turn-on voltage. Extracting these change rate characteristics can clearly identify the transition boundaries of each stage of the switching process in the time dimension, improving the accuracy of switching stage identification.

[0078] The gate voltage change rate and device voltage change rate obtained by the above method can simultaneously reflect the change in charge on the driving side and the voltage conversion behavior during the conduction process of the power device, so that the transient dynamic characteristics of the power device switching can be uniformly described in the form of change rate.

[0079] S3: Divide the switching process of the power device into stages based on the gate voltage change rate and the device voltage change rate.

[0080] Specifically, during the switching transients of power devices, the gate voltage change rate and the device voltage change rate exhibit different patterns in different switching stages. For example, during the initial gate charging stage, the gate voltage change rate typically shows a large positive change, while the voltage change rate across the device changes relatively little. During the Miller plateau modulation stage, the gate voltage change rate tends to decrease or even approach stability, while the voltage change rate across the device changes significantly. During the turn-on establishment stage, the gate voltage change rate changes again, while the voltage across the device gradually stabilizes. Therefore, this embodiment, by combining both the gate voltage change rate and the device voltage change rate, can more comprehensively characterize the dynamic features of the power device switching process and achieve stage division of the power device switching process.

[0081] In this embodiment, the gate voltage change rate and the device voltage change rate corresponding to the same sampling time are first combined to form a joint feature vector that can simultaneously reflect the dynamic characteristics of the driving side and the dynamic characteristics of the power circuit, and a joint feature sequence is formed according to the sampling time sequence.

[0082] Furthermore, after obtaining the joint feature sequence, the joint features corresponding to each sampling time are judged according to the preset stage state encoding rules, thereby obtaining the corresponding stage state identifier sequence. The stage state encoding rules are used to identify the current switching behavior of the power device based on the changing trends of the gate voltage change rate and the device voltage change rate. For example, when the gate voltage change rate is large and the device voltage change rate is small, it can be determined as the initial charging state of the gate; when the gate voltage change rate tends to level off and the device voltage change rate changes rapidly, it can be determined as the Miller plateau control state; when the gate voltage change rate changes again and the device voltage tends to stabilize, it can be determined as the conduction establishment state.

[0083] Furthermore, after obtaining the stage state identifier sequence, the positions where the state identifier changes between adjacent sampling times are used as candidate boundary points to obtain preliminary stage boundary positions. Specifically, by counting the number of continuous sampling points of the stage state before and after the candidate boundary point, the corresponding forward duration and backward duration can be obtained. When the state duration before and after a candidate boundary point is less than the preset minimum duration, the state change corresponding to that boundary point can be determined to be a short-term fluctuation, and thus it can be eliminated. At the same time, when the time interval between adjacent candidate boundary points is less than the preset minimum stage interval, the adjacent candidate boundary points can be merged to avoid too many divisions within the same switching stage, thereby improving the stability of the stage division results.

[0084] After obtaining the filtered target boundary point sequence, the switching process of the power device can be divided into multiple consecutive time intervals based on this sequence. For each time interval, the frequency of occurrence of each stage status identifier within the interval is counted, and the status identifier with the most frequent occurrence is determined as the dominant status identifier of the interval, thereby determining the switching stage type corresponding to the interval.

[0085] Using the above method, the switching process of power devices can be divided into several switching stages with clear physical meanings, such as the initial gate charging stage, the Miller plateau modulation stage, and the turn-on establishment stage. This stage division method based on dual rate-of-change characteristics can more accurately reflect the dynamic behavior of power devices during switching transients, making the boundary identification between different stages clearer and more reliable.

[0086] S4: Establish corresponding drive current envelope functions for different switching stages, and correct the parameters of the drive current envelope function corresponding to the current switching stage according to the device voltage change rate.

[0087] Specifically, the drive current requirements differ during the gate driving process of power devices at different switching stages. For example, in the initial gate charging stage, a larger drive current is needed to quickly establish the gate voltage, thereby shortening the time it takes for the device to enter the conduction region. During the Miller plateau control stage, the voltage across the device is changing rapidly, so the drive current needs to be limited to suppress voltage overshoot and electromagnetic interference. In the conduction establishment stage, the device voltage gradually stabilizes, and the drive current should be gradually reduced to minimize energy loss due to over-driving. Therefore, this embodiment establishes corresponding drive current envelope functions for different stages based on the switching stage division, realizing staged adjustment of the drive current.

[0088] In this embodiment, firstly, based on the stage division of the power device switching process, a corresponding drive current envelope function is configured for each switching stage, thereby forming a set of stage drive current envelope functions. The drive current envelope function describes the trend of the drive current changing with time within the corresponding switching stage. For example, in the initial gate charging stage, a monotonically increasing rising drive current envelope function can be set to gradually increase the drive current and accelerate the gate charge injection process; in the Miller plateau control stage, a limited-amplitude drive current envelope function can be set to maintain the drive current within a certain range, thereby suppressing excessively rapid changes in device voltage; in the conduction establishment stage, a gradually decreasing decaying drive current envelope function can be set to gradually reduce the drive current, achieving a smooth transition to the conduction state.

[0089] Furthermore, after establishing the drive current envelope function for each switching stage, corresponding initial function parameters can be set for each envelope function. The function parameters may include at least one of a current amplitude parameter, a change slope parameter, and a duration parameter. Specifically, the current amplitude parameter determines the amplitude range of the drive current in that stage, the change slope parameter controls the rate of change of the drive current over time, and the duration parameter defines the time interval for the change of the drive current in that stage.

[0090] However, in actual operation, the rate of voltage change across the power device is affected by factors such as bus voltage, load conditions, and device temperature, leading to deviations between the device voltage change rate and the expected rate. If the drive current envelope function parameter is fixed, the device voltage may change too quickly or too slowly, affecting switching performance. Therefore, this embodiment uses the device voltage change rate to correct the drive current envelope function parameter for the current switching stage, allowing the drive current to adapt to the actual switching state. Specifically, the device voltage change rate is acquired at the current sampling moment, and a reference value for the target device voltage change rate for this switching stage is determined. This reference value represents the expected voltage change rate for this switching stage. Subsequently, the difference between the actual and target device voltage change rates is calculated to obtain the deviation value, reflecting the degree of deviation of the current voltage change rate from the target rate.

[0091] Furthermore, the deviation value of the device voltage change rate is input into a preset parameter mapping rule to obtain the corresponding function parameter correction amount. This parameter mapping rule is used to establish the correspondence between the deviation of the device voltage change rate and the adjustment range of the drive current envelope function parameter. For example, when the device voltage change rate is greater than the target reference value, the drive current amplitude or the change slope is appropriately reduced to slow down the voltage change rate; when it is less than the target reference value, the drive current amplitude or the change slope is appropriately increased to improve the switching speed.

[0092] After obtaining the function parameter correction, the drive current envelope function parameters corresponding to the current switching stage are updated to obtain the target drive current envelope function. In this way, the drive current envelope function not only reflects the control requirements of different switching stages but also dynamically adjusts according to the actual changes in the device voltage rate of change, ensuring that the gate drive current effectively suppresses voltage overshoot and electromagnetic interference while maintaining switching efficiency.

[0093] By combining the aforementioned staged driving with dynamic parameter correction, an adaptive driving current regulation strategy can be formed during the switching process of power devices. This allows the driving current to not only meet the basic requirements of different switching stages but also to be dynamically adjusted in real time according to the actual switching process, thereby achieving multi-objective optimization control of the switching process of power devices.

[0094] S5: Generate a target gate drive current based on the parameter-corrected drive current envelope function, and adjust the output drive current of the gate optocoupler according to the target gate drive current.

[0095] Specifically, after parameter correction of the drive current envelope function, the target drive current envelope function can reflect the changing trend of the gate drive current adapted to the current switching stage. However, this function is a continuously changing current description and needs to be converted into specific drive current values ​​at discrete sampling times to form a target gate drive current sequence. Discretizing it in the time dimension allows us to obtain the target gate drive current values ​​at each sampling time, thereby achieving fine-grained control of the power device switching process.

[0096] In this embodiment, based on the target drive current envelope function of the current switching phase and the preset sampling period, the target gate drive current value at each sampling moment is calculated, generating a target drive current sequence corresponding to the time series, thereby causing the drive current to adjust according to the trend described by the envelope function. For example, during the initial gate charging phase, the target drive current sequence gradually increases; during the Miller plateau control phase, the target drive current sequence fluctuates within a limited range; and during the turn-on establishment phase, the target drive current sequence gradually decreases and tends to stabilize.

[0097] Furthermore, after obtaining the target drive current sequence, it needs to be converted into a corresponding gate optocoupler output regulation control quantity. This control quantity characterizes the degree of drive regulation at each sampling moment, so that the drive current output by the gate optocoupler approaches the target value. Establishing the correspondence between the target drive current and the optocoupler output regulation quantity enables dynamic control of the gate optocoupler output current.

[0098] Furthermore, at each sampling moment during the switching process, the output drive current of the gate optocoupler is adjusted according to the optocoupler output regulation control quantity to approximate the target value. As the sampling moment is updated, the output drive current of the gate optocoupler dynamically changes according to the target drive current sequence, forming a waveform that conforms to the law of the drive current envelope function.

[0099] Using the above method, the drive current envelope function can describe the changing trend of the drive current. After discretization calculation, it is transformed into a control sequence, enabling the gate drive current to be adjusted according to a predetermined strategy. This method can meet the drive requirements of different switching stages of power devices, adaptively adjust when the device voltage change rate changes, improve switching speed, suppress voltage overshoot and electromagnetic interference, and enhance the stability and reliability of the power device drive process.

[0100] For example, in this embodiment, a calculation example of a gate optocoupler current regulation method for the turn-on process of a power MOSFET is given to illustrate the implementation details of the solution in a single turn-on process. This method implements closed-loop control according to the chain of "voltage sampling—dual rate of change calculation—stage division—stage envelope function configuration—parameter correction—control quantity conversion—dynamic adjustment of optocoupler output," thereby suppressing voltage overshoot and electromagnetic interference caused by excessively rapid changes in device voltage while ensuring switching speed.

[0101] First, a sampling period of 20 ns is set, and the gate voltage and the voltage across the device are simultaneously acquired during a turn-on process. Assume that in consecutive sampling points, the gate voltage gradually increases from 2.1V, 2.8V, 3.5V, 4.1V, 4.3V, 4.4V, 5.0V, to 5.8V, while the voltage across the device gradually decreases from 600V, 598V, 596V, 520V, 410V, 280V, 65V, to 18V. The rate of change of the gate voltage and the rate of change of the device voltage can be obtained based on the difference between adjacent sampling points. After state encoding based on a preset judgment threshold, the first three sampling intervals are determined as the initial gate charging stage, the middle three sampling intervals as the Miller plateau control stage, and the last two sampling intervals as the conduction establishment stage. If a certain intermediate sampling point experiences a short-term state change due to noise, but the duration before and after the change is less than the preset minimum duration, then the candidate boundary point is removed. If the interval between two candidate boundary points is less than the preset minimum stage interval, then they are merged into the same stage boundary.

[0102] Furthermore, drive current envelope functions are configured for each of the three stages. In the example, a rising envelope function is used for the initial gate charging stage, with the initial drive current set to 0.20A, the rising slope set to 0.015A / 20ns, and the maximum drive current set to 0.50A; a limiting envelope function is used for the Miller plateau control stage, with the reference drive current set to 0.32A and the upper and lower limits set to 0.28A and 0.36A, respectively; and a decaying envelope function is used for the turn-on establishment stage, with the initial drive current set to 0.30A and the target steady-state drive current set to 0.12A. If the reference value for the target device voltage change rate obtained from the Miller plateau stage calibration is -1.8V / ns, while the measured device voltage change rate at the current sampling time is -2.2V / ns, it indicates that the device voltage drops too quickly. Based on the deviation calculation results, the parameters of the limiting envelope function for the current stage are corrected, for example, by reducing the reference drive current from 0.32A to 0.29A and keeping it within the preset upper and lower limits, thus obtaining the corrected target drive current envelope function.

[0103] Subsequently, the target drive current sequence is generated according to the sampling time sequence based on the corrected envelope function. For example, the target drive current sequences obtained in the above three stages are as follows: initial charging stage 0.20A, 0.35A, 0.50A; Miller plateau control stage 0.29A, 0.30A, 0.29A; conduction setup stage 0.22A, 0.15A. Then, according to the pre-calibrated target drive current-optocoupler output regulation control quantity inverse mapping relationship, the target drive current value at each sampling time is converted into the corresponding digital control code value. For example, 0.20A corresponds to control code value 42, 0.35A corresponds to control code value 71, 0.50A corresponds to control code value 96, 0.29A corresponds to control code value 61, 0.30A corresponds to control code value 63, 0.22A corresponds to control code value 48, and 0.15A corresponds to control code value 35. After applying a variation limit to the control quantity at adjacent sampling times, the result is sequentially applied to the gate optocoupler, causing the optocoupler output drive current to change dynamically with time.

[0104] As can be seen from this example, within the same turn-on process, it is possible to complete the identification of dual rate of change stages, configuration of staged drive current envelope functions, parameter correction based on device voltage rate of change deviation, and conversion and dynamic adjustment of optocoupler output control quantities. This achieves the synergistic control effect of rapid drive in the initial charging stage, limited adjustment in the Miller plateau stage, and smooth reduction of drive current in the conduction establishment stage.

[0105] The specific steps of S2 are as follows:

[0106] S2.1: The gate voltage and the voltage across the power device are continuously sampled at a preset sampling period to obtain the gate voltage sampling sequence and the device voltage sampling sequence.

[0107] Specifically, the switching process of power devices is short in duration and involves rapid voltage changes. If the sampling interval is too large, key transient characteristics such as the rise in gate voltage, the Miller plateau change, and the rapid drop in voltage across the device may be missed, thus affecting the accuracy of subsequent rate of change calculations and stage division. Therefore, this embodiment uses a preset sampling period to continuously sample the gate voltage and the voltage across the power device to ensure that the dynamic information during the switching process is completely preserved.

[0108] In this embodiment, the gate voltage and the voltage across the power device are synchronously sampled using a unified time reference, so that each sampling moment corresponds to a set of gate voltage values ​​and device voltage values. Arranged according to the sampling time sequence, these form a gate voltage sampling sequence and a device voltage sampling sequence, respectively. This method ensures that the time correspondence remains consistent when performing differential calculations on the two types of voltage signals, thereby improving the reliability of the calculated results for the gate voltage change rate and the device voltage change rate.

[0109] S2.2: Calculate the gate voltage change rate based on the ratio of the gate voltage difference between adjacent sampling times to the preset sampling period.

[0110] In this embodiment, firstly, the gate voltage values ​​corresponding to two adjacent sampling times are selected according to the gate voltage sampling sequence, and the voltage difference between them is calculated. Then, this voltage difference is compared with a preset sampling period to obtain the gate voltage change rate at the corresponding sampling time. By performing the above calculations sequentially on the entire gate voltage sampling sequence, a gate voltage change rate sequence corresponding to the sampling time sequence can be formed.

[0111] Furthermore, since the sampling period remains constant, the calculated rate of change can accurately reflect the rate of change of the gate voltage per unit time by calculating the ratio between the voltage difference and the sampling period. This rate of change not only characterizes the rising or falling trend of the gate voltage but also reflects the speed of the change process, thus providing an important basis for identifying different stages in the switching process of power devices.

[0112] S2.3: Calculate the device voltage change rate based on the ratio of the device voltage difference between adjacent sampling times to the preset sampling period.

[0113] In this embodiment, firstly, the device voltage values ​​corresponding to two adjacent sampling times are selected according to the device voltage sampling sequence, and the voltage difference between the two is calculated. Then, this voltage difference is compared with the preset sampling period to obtain the device voltage change rate at the corresponding sampling time. By performing differential calculations sequentially on the entire device voltage sampling sequence, a device voltage change rate sequence corresponding to the time series can be formed.

[0114] Furthermore, since the sampling period remains constant, the calculated rate of change of device voltage can accurately reflect the rate of change of device voltage per unit time by calculating the ratio between the voltage difference and the sampling period. When the rate of change of device voltage is a large negative value, it usually indicates that the voltage across the device is in a rapid decreasing phase; when the rate of change gradually approaches zero, it indicates that the device voltage is approaching a stable state.

[0115] The specific steps for S3 are as follows:

[0116] S3.1: Combine the gate voltage change rate and device voltage change rate corresponding to the same sampling time to generate a joint feature vector, and form a joint feature sequence according to the sampling time sequence.

[0117] Specifically, during the switching process of power devices, the gate voltage change rate primarily reflects the charge injection rate on the gate side, while the device voltage change rate reflects the voltage transition speed during the device's turn-on or turn-off process in the power circuit. These two types of change rates describe the dynamic behavior of the drive side and the power side, respectively. Analyzing based on only one characteristic can easily lead to incomplete identification or judgment errors in the switching phase. Therefore, this embodiment combines the two types of change rates, enabling the drive dynamics and power dynamics during the switching process to be described in the same feature space, thereby improving the accuracy of subsequent phase identification.

[0118] In this embodiment, for each sampling moment, the corresponding gate voltage change rate and device voltage change rate are combined to form a joint feature vector containing two feature components. This joint feature vector can simultaneously reflect the gate voltage change rate and the device voltage change rate at that moment, thereby establishing a correspondence between driving behavior and device response at a single point in time.

[0119] Furthermore, the joint feature vectors at each sampling time are arranged in chronological order to form a joint feature sequence. This sequence continuously records the coordinated dynamic process of drive-side changes and device voltage changes during the switching process of the power device, enabling subsequent steps to perform a holistic analysis of the switching behavior based on this joint feature sequence.

[0120] S3.2: Input the joint feature sequence into the preset stage state encoding rule to obtain the stage state identifier sequence corresponding to each sampling time.

[0121] In this embodiment, each joint feature vector in the joint feature sequence is first analyzed, and its state is determined according to a preset stage state encoding rule. The stage state encoding rule is used to establish the correspondence between the combined features of gate voltage change rate and device voltage change rate and the switching stage, thereby converting continuously changing feature data into stage state identifiers with clear physical meaning.

[0122] Specifically, the stage state encoding rule includes: determining the stage state identifier corresponding to the current sampling time based on the comparison results of the gate voltage change rate and device voltage change rate corresponding to each sampling time with the preset judgment conditions; and correcting or eliminating state transitions that do not conform to the stage change sequence according to the preset sequence relationship of stage states.

[0123] The preset determination conditions include at least the following: when the gate voltage change rate is greater than a first threshold and the absolute value of the device voltage change rate is less than a second threshold, it is determined to be the initial gate charging state; when the gate voltage change rate is within a preset plateau change range and the absolute value of the device voltage change rate is greater than a third threshold, it is determined to be the Miller plateau control state; when the absolute value of the device voltage change rate is less than a fourth threshold and the gate voltage continues to rise, it is determined to be the conduction establishment state. The preset sequence of the stage states is: initial gate charging state, Miller plateau control state, conduction establishment state; when the state change at adjacent sampling times does not conform to the sequence relationship, the corresponding state change is determined to be a transient disturbance, and the previous stable state identifier is maintained or the sampling position corresponding to the state change is removed.

[0124] In this embodiment, the first threshold, second threshold, third threshold, and fourth threshold are determined based on the calibration switching waveform of the target device under preset test conditions. Specifically, the maximum value of the gate voltage change rate sequence during calibration is obtained as the gate change rate peak value, and the maximum value of the absolute value sequence of device voltage change rate is obtained as the device change rate peak value. Each threshold is then determined according to a preset ratio. Preferably, the first threshold is 0.5 to 0.8 times the gate change rate peak value, the second threshold is 0.05 to 0.2 times the device change rate peak value, the third threshold is 0.3 to 0.7 times the device change rate peak value, and the fourth threshold is 0.05 to 0.2 times the device change rate peak value. The second and fourth thresholds can be set to the same value, or they can be set separately based on the device voltage stability after the Miller plateau is completed.

[0125] Furthermore, for each sampling moment in the joint feature sequence, the stage state identifier corresponding to that sampling moment is determined based on the numerical range and trend of the corresponding gate voltage change rate and device voltage change rate. This stage state identifier can be used to indicate the switching behavior category corresponding to the current moment, such as the initial gate charging state, Miller plateau control state, or conduction establishment state.

[0126] By sequentially encoding the state of all sampling moments in the joint feature sequence, a stage state identifier sequence corresponding one-to-one with the time series can be obtained. This sequence reflects the changes in stage states during the switching process of the power device in the time dimension, providing a reliable basis for identifying stage boundary points and dividing the switching process into stages by identifying the locations of state changes.

[0127] S3.3: Using the sampling positions where the state identifiers of adjacent sampling times in the stage state identifier sequence change as candidate boundary points, the candidate boundary points are filtered and merged based on the state duration before and after the candidate boundary points and the interval between the candidate boundary points to obtain the stage boundary point sequence.

[0128] Specifically, in this embodiment, the stage state identifier sequence is first traversed. When a difference in state identifiers is detected between adjacent sampling times, the sampling position corresponding to the next sampling time is determined as the initial candidate boundary point. Subsequently, for each candidate boundary point, the number of sampling points whose previous state remains unchanged and the number of sampling points whose next state remains unchanged are counted, and these are respectively used as the forward duration and the backward duration. If the forward duration or the backward duration is less than a preset minimum duration, the state change corresponding to the candidate boundary point is considered to be a short-term disturbance, and the candidate boundary point is removed.

[0129] Further, the candidate boundary points, after being filtered by duration, are arranged in order of sampling time, and the interval between adjacent candidate boundary points is calculated. If the interval between two or more adjacent candidate boundary points is less than the preset minimum stage interval, these two or more adjacent candidate boundary points are divided into the same candidate point group, and the candidate point group is merged. During the merging process, preferably, the stability evaluation value of each candidate boundary point within the same candidate point group is calculated, and the candidate boundary point with the largest stability evaluation value is determined as the target boundary point after merging. The stability evaluation value is determined based on the forward and backward duration of the corresponding candidate boundary point. When two or more candidate boundary points within the same candidate point group have the same stability evaluation value, the intermediate sampling position between the first and last candidate boundary points within the candidate point group is determined as the target boundary point after merging. After merging all candidate point groups, the resulting target boundary points are arranged in chronological order to form a stage boundary point sequence.

[0130] By performing the above screening and merging process on the candidate boundary points, invalid boundary points generated by short-term disturbances can be removed, while key positions that can stably reflect the stage transition can be retained, thus forming a stage boundary point sequence.

[0131] S3.4: Divide the switching process of the power device into stages according to the stage boundary point sequence.

[0132] Specifically, after obtaining the sequence of stage boundary points, these boundary points can be used to divide the entire switching process into multiple consecutive time intervals on the time axis. Each time interval corresponds to a relatively stable state change process. By performing statistical analysis on the stage state markers within the interval, the main switching stage corresponding to that interval can be determined.

[0133] In this embodiment, the positions of each boundary point are first determined in the sampling time series based on the stage boundary point sequence, and the switching process of the power device is divided into multiple consecutive time intervals according to the time sequence. Each time interval is defined by two adjacent stage boundary points and contains several consecutive sampling points and corresponding stage state identifiers.

[0134] Furthermore, for each time interval, the frequency of occurrence of each stage state identifier within that interval is counted, and the state identifier with the highest frequency is determined as the dominant state identifier for that interval. This method avoids the impact of state fluctuations at individual sampling points on the stage segmentation results, thereby improving the stability of stage identification.

[0135] After determining the dominant state identifier for each timing interval, the corresponding switching stage label is assigned to the corresponding timing interval based on the state identifier, thus obtaining the complete switching stage division result. For example, different intervals can be labeled as the gate initial charging stage, the Miller plateau control stage, and the turn-on establishment stage, etc.

[0136] By using the above method, the switching process of power devices can be divided into multiple stages with clear physical meanings. The drive current can be adjusted according to the dynamic characteristics of different stages, thereby achieving fine control of the switching process of power devices.

[0137] The specific steps of S3.3 are as follows:

[0138] S3.3.1: For each candidate boundary point, count the number of continuous sampling points of its adjacent state identifiers before and after it to obtain the forward duration and backward duration.

[0139] In this embodiment, for each candidate boundary point, the stage state identifier sequence is first traversed forward from the boundary point, and the number of sampling points that maintain the same state identifier continuously before the boundary point is counted, thereby obtaining the corresponding forward duration. This forward duration is used to reflect the stable duration of the stage state before the boundary point.

[0140] Furthermore, starting from the same candidate boundary point, the sequence of stage state identifiers is traversed backward, and the number of sampling points that maintain the same state identifier continuously after the boundary point is counted, thus obtaining the corresponding backward persistence length. This backward persistence length is used to represent the degree of persistence of the stage state after the boundary point.

[0141] By obtaining the number of continuous sampling points before and after the candidate boundary point, it can be determined whether the state change corresponding to that position has stable stage transition characteristics. When the state before and after the boundary point has a certain number of continuous sampling points, it usually indicates that the position is more likely to correspond to a real stage transition; while when the duration is short, it may be a state change caused by short-term fluctuations.

[0142] S3.3.2: Calculate the interval between adjacent candidate boundary points based on the preset sampling period and the sampling positions of adjacent candidate boundary points.

[0143] In this embodiment, based on the position index of adjacent candidate boundary points in the sampling sequence, the number of sampling point intervals between two candidate boundary points is first calculated. Then, this number of sampling point intervals is multiplied by a preset sampling period to obtain the corresponding time interval, i.e., the interval duration between adjacent candidate boundary points.

[0144] Furthermore, this interval length can reflect the duration of the corresponding stage change between two candidate boundary points. A longer interval length usually indicates that there is a relatively stable stage interval between the two boundary points; while a shorter interval length indicates that there may be continuous changes within a short period of time within that interval.

[0145] S3.3.3: When the forward duration or backward duration is less than the preset minimum duration, the corresponding candidate boundary point is removed.

[0146] In this embodiment, for each candidate boundary point, the stability of the states before and after the boundary point is first evaluated using the forward duration and backward duration. If the state before or after the candidate boundary point lasts for only a very small number of sampling points, it indicates that the state change may be a short-term fluctuation rather than a true switching phase transition.

[0147] Furthermore, the forward duration and backward duration are compared with a preset minimum duration. If either duration is less than the preset minimum duration, the state change corresponding to the candidate boundary point is considered to lack stable stage characteristics, and therefore the candidate boundary point is removed from the candidate set.

[0148] The above method can effectively filter out false boundary points caused by short-term noise or local disturbances, making the remaining candidate boundary points more reflective of the true stage transition position.

[0149] S3.3.4: When the interval between adjacent candidate boundary points is less than the preset minimum stage interval, the adjacent candidate boundary points are merged.

[0150] In this embodiment, the interval between adjacent candidate boundary points is first used, and this interval is compared with a preset minimum stage interval. When the interval is less than the preset minimum stage interval, it is considered that the state change between the two candidate boundary points is insufficient to constitute a complete and stable switching stage.

[0151] Furthermore, for adjacent candidate boundary points that meet the above conditions, they are merged, so that multiple candidate boundary points with short intervals are combined into a single stage boundary point. In this way, continuous fluctuations generated during the transition of the same stage can be uniformly merged into a single effective stage boundary, thereby reducing the generation of redundant boundary points.

[0152] By performing the above merging process, the retained stage boundary points can better reflect the actual changing patterns of the switching stages, thereby improving the stability and accuracy of the stage division results.

[0153] S3.3.5: The candidate boundary points after elimination and merging are determined as the target boundary point sequence.

[0154] In this embodiment, the candidate boundary points are sorted according to the sampling time order, and their position indices in the sampling sequence are recorded. In this way, a set of boundary points arranged in ascending order of time can be formed.

[0155] Furthermore, this set of boundary points is defined as the target boundary point sequence. The target boundary point sequence is used to represent the key transition positions between different stages in the switching process of the power device, and divides the entire switching process into multiple relatively stable intervals on the time axis.

[0156] By obtaining a stable sequence of target boundary points, misjudgments caused by noise fluctuations or short-term state changes can be effectively reduced, making the stage boundary more consistent with the dynamic characteristics of the actual switching process of power devices.

[0157] The specific steps in S3.4 are as follows:

[0158] S3.4.1: Based on the target boundary point sequence, the switching process of the power device is divided into multiple continuous time intervals.

[0159] Specifically, after obtaining a stable sequence of target boundary points, these boundary points can be used to segment the entire switching process on the time axis. Since the target boundary points have undergone duration length filtering and interval merging, their positions can accurately reflect the transition boundaries between different switching stages, and therefore can be used as the basis for dividing time series intervals.

[0160] In this embodiment, the interval range between each boundary point is determined sequentially according to the position index of the target boundary point in the sampling sequence. Specifically, the sampling data corresponding to the switching process of the power device is divided into multiple continuous time intervals using two adjacent target boundary points as interval boundaries. At the same time, the interval between the start position of the switching process and the first target boundary point, and the interval between the last target boundary point and the end of the switching process are also recorded as independent time intervals.

[0161] Using the above method, the complete switching process can be divided into several time-series intervals that are continuous and do not overlap. Each interval usually corresponds to relatively stable state change characteristics.

[0162] S3.4.2: For each time series interval, count the number of times each stage status identifier appears in the time series interval, and determine the stage status identifier with the most occurrences as the dominant status identifier of the time series interval.

[0163] Specifically, within the same time interval, the stage status identifier may fluctuate slightly due to sampling noise or transient disturbances. Directly judging based on the status of a single sampling point can easily lead to unstable stage identification. Therefore, this embodiment uses statistical analysis of the status identifiers within the interval to determine the dominant state that represents the overall characteristics of the interval.

[0164] In this embodiment, for each time interval, the stage state identifiers corresponding to all sampling points within the interval are first traversed, and the frequency of occurrence of different state identifiers within the interval is counted. Through this statistical process, the distribution of various state identifiers within the interval can be obtained.

[0165] Furthermore, the stage state identifier that appears most frequently is determined as the dominant state identifier for that time series interval. This dominant state identifier can reflect the most representative stage characteristics within that interval, thereby mitigating the impact of state fluctuations at individual sampling points to some extent.

[0166] The dominant state identifier determined by the above method can be used as the basis for determining the corresponding switching stage of the time interval, making the stage identification results more stable and reliable.

[0167] S3.4.3: Based on the dominant state identifier corresponding to each time interval, assign a corresponding switching stage label to each time interval to obtain the stage division result of the power device switching process. The stage division result includes the gate initial charging stage, the Miller plateau control stage, and the conduction establishment stage.

[0168] In this embodiment, each timing interval is mapped to a corresponding switching stage label based on the dominant state identifier corresponding to each timing interval. For example, when the dominant state identifier corresponds to the characteristic of a rapid rise in gate voltage and a small change in device voltage, the interval can be marked as the initial gate charging stage; when the dominant state identifier shows that the gate voltage change tends to level off and the device voltage drops rapidly, the interval can be marked as the Miller plateau control stage; when the device voltage gradually stabilizes and the gate voltage continues to rise to a stable value, the interval can be marked as the turn-on establishment stage.

[0169] By assigning stage labels to all timing intervals sequentially, a complete stage division of the power device switching process can be obtained. This result clearly reflects the entire process of the power device from gate charging to voltage conversion and then to conduction establishment in the time dimension, providing a basis for establishing corresponding drive current regulation strategies for different switching stages, thereby achieving fine-grained control of the switching process.

[0170] The specific steps for S4 are as follows:

[0171] S4.1: Based on the stage division results of the power device switching process, configure the corresponding drive current envelope function for each switching stage to obtain the stage drive current envelope function set.

[0172] Specifically, since the gate drive current requirements vary significantly at different stages, adopting a uniform drive strategy can easily lead to problems such as unstable switching speed or voltage overshoot. Therefore, it is necessary to construct corresponding drive current envelope functions for different stages.

[0173] In this embodiment, based on the stage division results, a corresponding drive current envelope function is configured for each switching stage to describe the target trend of the gate drive current changing with time within that stage. For example, in the initial gate charging stage, a rising drive current envelope function can be configured to enable the gate capacitance to quickly build up voltage; in the Miller plateau control stage, a relatively smooth or controlled change in drive current envelope function can be configured to suppress electromagnetic interference caused by rapid changes in device voltage; and in the conduction establishment stage, a gradually stabilizing drive current envelope function can be configured to ensure a smooth establishment of the device's conduction state.

[0174] In this embodiment, the drive current envelope function corresponding to each switching stage is described using a time function with the stage start time as zero. For the first... Each switching phase is denoted as a relative time. ,in This marks the start time of this phase.

[0175] For the initial gate charging phase, a rising drive current envelope function is preferred:

[0176]

[0177] in, This is the initial drive current. The slope of the current rise, This is the maximum drive current during this stage. This refers to the duration of this phase.

[0178] For the Miller platform control phase, the preferred configuration is a limited-amplitude drive current envelope function:

[0179]

[0180] in, This serves as the reference drive current for this stage. and These are the lower and upper limits of the drive current, respectively. This is the correction amount obtained based on the deviation of the device voltage change rate. The duration of this phase, This represents a limiting function, which restricts the input to a certain value. Within the range.

[0181] For the conduction setup phase, a decaying drive current envelope function is preferred:

[0182]

[0183] in, This is the initial drive current for this stage. For the target steady-state drive current, The attenuation coefficient is... This refers to the duration of this phase. The attenuation coefficient... This characterizes the rate at which the drive current decays towards the target steady-state drive current during the conduction setup phase. Preferably, it is based on the duration of the conduction setup phase. And the allowable deviation ratio of the drive current to the target steady-state drive current at the end of the stage. Determine the attenuation coefficient This makes in At that time, the difference between the target driving current and the target steady-state driving current is not greater than the initial difference of the stage. times, of which, The preset value is between 0.01 and 0.10. Based on the above relationship, the attenuation coefficient... satisfy:

[0184]

[0185] This allows the drive current during the conduction setup phase to smoothly decay to near the target steady-state drive current within a preset phase duration.

[0186] Preferably, the envelope functions of adjacent stages satisfy the function value continuity at the stage boundary point, so that the initial current value of the envelope function of the next stage is equal to the output value of the envelope function of the previous stage at the end of the stage.

[0187] By configuring drive current envelope functions for each switching stage, a set of stage drive current envelope functions can be formed. This set describes the drive current variation pattern at different stages of the entire switching process, providing a basis for parameter correction of the envelope function based on the real-time device voltage change rate, thereby achieving more refined gate drive control.

[0188] S4.2: For the driving current envelope function corresponding to each switching stage, determine the corresponding initial function parameters, wherein the initial function parameters include at least one of the current amplitude parameter, the change slope parameter, and the duration parameter.

[0189] In this embodiment, initial function parameters are determined for the drive current envelope function corresponding to each switching stage. The initial function parameters may include at least one of a current amplitude parameter, a slope parameter, and a duration parameter. Specifically, the current amplitude parameter defines the target amplitude range of the drive current in that stage; the slope parameter describes the rate of increase or decrease of the drive current over time; and the duration parameter characterizes the effective range of the drive current envelope function on the time axis in that stage.

[0190] S4.3: Calculate the function parameter correction amount for the current switching stage based on the device voltage change rate corresponding to the current sampling time.

[0191] In this embodiment, the corresponding device voltage change rate is acquired at the current sampling time and compared with the reference voltage change rate at the current switching stage. If the actual voltage change rate is higher than the reference value, the corresponding function parameter correction is calculated based on the difference between the two to reduce the growth rate or amplitude of the drive current; if the actual voltage change rate is lower than the reference value, the corresponding correction is calculated to increase the intensity of the drive current change, thereby accelerating the voltage conversion process.

[0192] Specifically, in this embodiment, let the current switching stage be the first... In this phase, the rate of change of device voltage at the current sampling moment is obtained. And determine the reference value of the target device voltage change rate corresponding to this stage. The reference value for the target device voltage change rate at each stage is determined based on the calibration switching waveform of the target device under preset test conditions. The deviation value of the change rate at the current stage is calculated based on the difference between the device voltage change rate and the reference value for the target device voltage change rate.

[0193]

[0194] Preferably, the deviation value of the rate of change is normalized to obtain a normalized deviation value:

[0195]

[0196] in, To prevent the use of default positive numbers with a denominator of zero.

[0197] Further, the function parameter correction for the current switching stage is calculated based on the normalized deviation value. Assume the envelope function parameters corresponding to the current stage include amplitude parameters. , changing parameters and duration parameters If at least one of them is true, then the corresponding parameter correction amount satisfies:

[0198]

[0199] in, , and This refers to the parameter correction coefficient corresponding to the current stage. The parameter correction coefficient is set separately for different switching stages to ensure that the drive current adjustment sensitivity of each stage matches the control requirements of that stage.

[0200] Preferably, when the absolute value of the normalized deviation is not greater than a preset deviation dead zone threshold, the envelope function parameters for the current stage are not corrected; when the absolute value of the normalized deviation is greater than the preset deviation dead zone threshold, the corresponding function parameter correction amount is calculated according to the parameter correction coefficient. Furthermore, upper and lower limits are set for the corrected parameters to ensure they meet a preset parameter range, thereby preventing excessively large drive current adjustments that could lead to control instability.

[0201] Furthermore, the function parameter correction can be applied to at least one of the current amplitude parameter, the slope parameter, or the duration parameter. For example, when the voltage change rate is too large, the current amplitude or the slope can be appropriately reduced; when the voltage change rate is too small, the current amplitude or the slope can be appropriately increased. In this way, the drive current envelope function can be dynamically adjusted according to the real-time voltage change characteristics, maintaining a balance between speed and stability in the switching process, thereby improving the precision of power device switching control.

[0202] S4.4: Update the parameters of the drive current envelope function corresponding to the current switching stage according to the function parameter correction amount to obtain the target drive current envelope function.

[0203] In this embodiment, the driving current envelope function parameters corresponding to the current switching stage are adjusted according to the function parameter correction amount. Specifically, the function parameter correction amount is superimposed or corrected to the corresponding initial function parameters to update at least one of the current amplitude parameter, change slope parameter, or duration parameter, thereby obtaining an updated set of function parameters.

[0204] Furthermore, the driving current envelope function for the current stage is reconstructed based on the updated function parameters, so that it can reflect the changing trend of the driving current after real-time correction. The driving current envelope function obtained in this way is the target driving current envelope function.

[0205] Specifically, in this embodiment, let the current switching stage be the first... Phase, the first The driving current envelope function corresponding to the stage is expressed as:

[0206]

[0207] in, This refers to the relative time within the current switching phase. This is the envelope function parameter vector corresponding to the current stage. The envelope function parameter vector includes at least one of the following: amplitude parameter, variation parameter, and duration parameter. For the first The envelope function expression used in each stage, Indicates the first Each stage, with a relative timeframe as follows: At that time, the corresponding target drive current value. Adjusted based on the function parameters corresponding to the current stage. The current envelope function parameter vector is updated to obtain the intermediate parameter vector:

[0208]

[0209] Preferably, preset upper and lower limit constraints are applied to each parameter in the intermediate parameter vector to obtain the updated target parameter vector:

[0210]

[0211] in, This represents a parameter limiting function, used to restrict each updated parameter to a corresponding preset parameter range. Subsequently, the target parameter vector is substituted into the driving current envelope function corresponding to the current stage to obtain the target driving current envelope function for the current stage:

[0212]

[0213] Specifically, the updated target drive current envelope function maintains the function change characteristics corresponding to the current stage; when the current stage is the gate initial charging stage, the drive current envelope function remains monotonically increasing; when the current stage is the Miller plateau control stage, the output of the drive current envelope function remains limited to the preset current range; when the current stage is the conduction establishment stage, the drive current envelope function remains monotonically decreasing and tends to the target steady-state drive current.

[0214] Through the above parameter update process, the drive current envelope function can be continuously adjusted according to the device voltage change characteristics during the switching process, thereby suppressing voltage overshoot and electromagnetic interference while ensuring switching speed, and improving the stability and control accuracy of the power device switching process.

[0215] The specific steps of S4.1 are as follows:

[0216] For the initial gate charging phase, a monotonically increasing rising drive current envelope function is configured;

[0217] For the Miller platform control phase, a limited-amplitude drive current envelope function is configured;

[0218] For the conduction setup phase, a monotonically decreasing decaying drive current envelope function is configured;

[0219] The drive current envelope functions corresponding to each switching stage are combined in stage order to obtain the stage drive current envelope function set.

[0220] Specifically, during the switching process of power devices, there are significant differences in the gate charge transfer mechanism and device voltage change characteristics at different stages. Therefore, it is necessary to design drive current envelope functions with different change characteristics for each stage in order to achieve fine control of the switching process.

[0221] In this embodiment, a monotonically increasing rising-mode drive current envelope function is first configured for the initial gate charging phase. During this phase, the gate capacitance begins to charge rapidly, and the voltage across the device remains relatively stable. Therefore, by gradually increasing the drive current amplitude, the gate voltage can be rapidly increased, thereby shortening the gate charging time and improving the switching response speed.

[0222] Furthermore, after entering the Miller plateau control phase, the device voltage begins to change rapidly, at which point the gate voltage enters a relatively stable Miller plateau region. To avoid voltage overshoot or electromagnetic interference caused by excessively rapid device voltage changes, this embodiment configures a limited-amplitude drive current envelope function to restrict the drive current, keeping the gate charge injection process controllable, thereby balancing switching speed and voltage change stability.

[0223] During the turn-on setup phase, the device voltage has essentially dropped to a stable value, while the gate voltage continues to rise and gradually enters the fully turn-on state. A monotonically decreasing decaying drive current envelope function is configured for this phase to gradually reduce the drive current, thereby ensuring turn-on setup while reducing subsequent energy injection and avoiding power loss due to over-driving.

[0224] Finally, the drive current envelope functions corresponding to the gate initial charging stage, Miller plateau regulation stage, and conduction establishment stage are combined according to the time sequence of these stages to form a set of stage drive current envelope functions. This set can completely describe the target change pattern of the drive current throughout the entire switching process of the power device, providing a basis for parameter correction based on the real-time voltage change rate.

[0225] The specific steps of S4.3 are as follows:

[0226] S4.3.1: Obtain the device voltage change rate corresponding to the current sampling time, and determine the reference value of the target device voltage change rate corresponding to the current switching stage.

[0227] In this embodiment, the corresponding device voltage change rate is first read at the current sampling time. This device voltage change rate is calculated from the device voltage difference between adjacent sampling times and a preset sampling period, thus reflecting the instantaneous change trend of the device voltage at the current moment.

[0228] Furthermore, based on the type of the current switching stage, a reference value for the target device voltage change rate corresponding to that stage is determined. The expected device voltage change rate differs across switching stages. For example, during the initial gate charging stage, the device voltage typically remains relatively stable, resulting in a smaller reference change rate; during the Miller plateau control stage, the device voltage begins to decrease rapidly, leading to a relatively larger reference change rate; and during the turn-on setup stage, the device voltage gradually stabilizes, causing the reference change rate to decrease again.

[0229] By setting corresponding target device voltage change rate reference values ​​for different switching stages, the real-time measured device voltage change rate can be compared with the reference value, thereby determining the correction direction and correction magnitude of the drive current envelope function parameters to achieve adaptive control of the switching process.

[0230] S4.3.2: Calculate the device voltage change rate deviation value based on the difference between the device voltage change rate and the target device voltage change rate reference value.

[0231] In this embodiment, the device voltage change rate at the current sampling moment is compared with the target device voltage change rate reference value for the corresponding stage, and the device voltage change rate deviation value is obtained by calculating the difference between the two. The deviation value reflects both the magnitude and direction of the deviation. A positive deviation value indicates that the actual voltage change rate is higher than the reference value, while a negative deviation value indicates that the actual voltage change rate is lower than the reference value.

[0232] Furthermore, by using the voltage change rate deviation value of this device, the degree of deviation between the voltage change state in the current switching stage and the target change state can be quantified, enabling the drive current regulation process to respond more accurately to real-time switching state changes.

[0233] S4.3.3: Input the device voltage change rate deviation value into a preset parameter mapping rule to obtain the function parameter correction amount for the current switching stage, wherein the parameter mapping rule is used to establish the correspondence between the device voltage change rate deviation value and the adjustment range of the drive current envelope function parameter.

[0234] In this embodiment, the calculated device voltage change rate deviation value is input into a pre-set parameter mapping rule, and the corresponding function parameter correction amount is determined according to the magnitude and sign of the deviation value. The parameter mapping rule is used to describe the correspondence between the device voltage change rate deviation and the adjustment range of the drive current envelope function parameter, and can take the form of proportional mapping, piecewise mapping, or lookup table mapping, for example.

[0235] Furthermore, when the deviation of the device voltage change rate is large, a larger function parameter correction amount is obtained through parameter mapping rules to enhance the adjustment range of the drive current; when the deviation is small, a smaller correction amount is obtained, thereby achieving a smoother drive regulation. In this way, the parameter change range of the drive current envelope function can be adaptively adjusted according to the real-time voltage change state, making the drive current regulation process more stable and continuous.

[0236] The specific steps for S5 are as follows:

[0237] S5.1: Based on the target drive current envelope function corresponding to the current switching stage, calculate the target gate drive current value corresponding to each sampling time according to the sampling time sequence, and generate the target drive current sequence.

[0238] In this embodiment, the target drive current envelope function is first determined based on the switching phase at the current sampling time. Then, with a preset sampling period as the time step, the function output value corresponding to each sampling time is calculated point by point according to the sampling sequence, and the function output value is used as the target gate drive current value at the corresponding time.

[0239] Furthermore, by arranging the target gate drive current values ​​calculated at each sampling time in chronological order, a target drive current sequence can be generated. This sequence can describe the target trajectory of the gate drive current changing over time during the current switching phase.

[0240] In the above manner, the continuous form of the drive current envelope function can be converted into a discrete form of the target drive current sequence, so that the drive current regulation process can be executed step by step according to the sampling timing.

[0241] S5.2: Convert the target drive current sequence into the corresponding optocoupler output regulation control quantity.

[0242] In this embodiment, a mapping relationship between the target drive current and the optocoupler output control quantity is first established based on the input-output characteristic curve of the gate optocoupler. Then, each drive current value in the target drive current sequence is converted one by one, and the corresponding optocoupler output adjustment control quantity is calculated based on the mapping relationship.

[0243] Specifically, in this embodiment, the optocoupler output adjustment control quantity is a control signal used to set the gate optocoupler output drive current. The control signal can be any one of a digital control code value, a pulse width modulation duty cycle, or an analog control voltage. Preferably, the optocoupler output adjustment control quantity is a digital control code value, which is converted from digital to analog to generate a corresponding current setting signal to control the gate optocoupler output drive current.

[0244] Furthermore, a mapping relationship between the target drive current and the optocoupler output regulation control quantity is pre-established based on the input-output transmission characteristics of the gate optocoupler. Specifically, under preset test conditions, control quantities with different values ​​are applied to the gate optocoupler, and the corresponding output drive currents are measured to obtain multiple control quantity-output current sample pairs; an inverse mapping relationship from the target drive current to the optocoupler output regulation control quantity is established based on the sample pairs. Preferably, the inverse mapping relationship is established using a piecewise linear mapping relationship or a lookup table interpolation mapping relationship to compensate for the nonlinear transmission characteristics of the gate optocoupler in different operating ranges.

[0245] For the first in the target drive current sequence Target drive current value The corresponding initial control quantity is calculated based on the inverse mapping relationship. The initial control quantity is then constrained at both upper and lower limits to obtain the optocoupler output adjustment control quantity at the current sampling time. Preferably, the variation range of the control quantity at adjacent sampling times is also limited to prevent excessive fluctuations in the gate optocoupler output drive current caused by sudden changes in the control quantity.

[0246] Furthermore, the converted control quantities are arranged according to the sampling time sequence to form an optocoupler output adjustment control sequence corresponding to the target drive current sequence. This control sequence can describe the optocoupler output adjustment amplitude to be applied at each sampling time, thereby enabling the optocoupler output drive current to change according to the target drive current sequence.

[0247] Through the above conversion process, the drive current control requirement can be transformed into an adjustment control quantity that can be directly applied to the gate optocoupler, so that the drive current adjustment process can be executed according to the predetermined target current trajectory.

[0248] S5.3: Dynamically adjust the output drive current of the gate optocoupler according to the optocoupler output adjustment control quantity corresponding to each sampling time.

[0249] In this embodiment, based on the control quantity corresponding to each sampling moment in the optocoupler output adjustment control sequence, the output adjustment state of the gate optocoupler is updated sequentially according to a preset sampling period, so that the optocoupler output drive current exhibits corresponding change amplitudes at different sampling moments. Through this point-by-point adjustment method, the actual output drive current can be gradually made to approach the target drive current sequence.

[0250] Specifically, in this embodiment, the optocoupler output adjustment control quantity corresponding to each sampling moment is sequentially applied to the gate optocoupler driving unit according to a preset sampling period, so that the gate optocoupler outputs a driving current corresponding to the target driving current value at each sampling moment. As the sampling moment is updated, the gate optocoupler output driving current dynamically changes according to the target driving current sequence, thereby forming an output driving current waveform consistent with the envelope function of the target driving current at different switching stages. Preferably, the optocoupler output adjustment control quantity is fine-tuned in a closed loop according to the deviation between the actual output driving current and the target driving current to improve the tracking accuracy of the gate optocoupler output driving current to the target driving current sequence.

[0251] Furthermore, the optocoupler output regulation control quantity is continuously updated according to the sampling timing throughout the switching process, so that the output drive current of the gate optocoupler changes according to the corresponding drive current envelope function at different switching stages. Through this dynamic adjustment method, voltage overshoot and electromagnetic interference can be effectively suppressed while ensuring switching speed, thereby achieving fine-grained drive control of the power device switching process.

[0252] Example 2

[0253] Please see Figure 2 The present invention provides an embodiment of a gate optocoupler current regulation system based on multi-objective complementary control. The system includes a voltage acquisition module, a rate of change calculation module, a stage division module, an envelope function generation module, a parameter correction module, and a drive adjustment module, wherein:

[0254] The voltage acquisition module is used to acquire the gate voltage and the voltage across the power device during the switching process of the power device.

[0255] The rate of change calculation module is used to calculate the gate voltage rate of change based on the gate voltage, and to calculate the device voltage rate of change based on the voltage across the power device.

[0256] The stage division module is used to divide the switching process of the power device into stages based on the gate voltage change rate and the device voltage change rate, and obtain stage division results for different switching stages.

[0257] The envelope function generation module is used to establish corresponding drive current envelope functions for different switching stages, thereby obtaining a set of stage drive current envelope functions.

[0258] The parameter correction module is used to correct the parameters of the drive current envelope function corresponding to the current switching stage according to the device voltage change rate, so as to obtain the target drive current envelope function.

[0259] The drive adjustment module is used to generate a target gate drive current based on the parameter-corrected drive current envelope function, and adjust the output drive current of the gate optocoupler according to the target gate drive current.

[0260] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A gate optocoupler current regulation method based on multi-objective complementary control, applied to the gate optocoupler driving process of power devices, characterized in that, The method includes: Obtain the gate voltage and the voltage across the power device during the switching process; Calculate the gate voltage change rate based on the gate voltage, and calculate the device voltage change rate based on the voltage across the power device; The switching process of the power device is divided into stages based on the gate voltage change rate and the device voltage change rate; For each of the different switching stages, a corresponding driving current envelope function is established, and the parameters of the driving current envelope function corresponding to the current switching stage are corrected according to the device voltage change rate. The target gate drive current is generated based on the parameter-corrected drive current envelope function, and the output drive current of the gate optocoupler is adjusted according to the target gate drive current.

2. The gate optocoupler current regulation method based on multi-objective complementary control according to claim 1, characterized in that, The step of calculating the gate voltage change rate based on the gate voltage and calculating the device voltage change rate based on the voltage across the power device includes: The gate voltage and the voltage across the power device are continuously sampled at a preset sampling period to obtain the gate voltage sampling sequence and the device voltage sampling sequence. The gate voltage change rate is calculated based on the ratio of the gate voltage difference between adjacent sampling times to the preset sampling period. The device voltage change rate is calculated based on the ratio of the device voltage difference at adjacent sampling times to the preset sampling period.

3. The gate optocoupler current regulation method based on multi-objective complementary control according to claim 1, characterized in that, The step-by-step division of the switching process of the power device based on the gate voltage change rate and the device voltage change rate includes: The gate voltage change rate and device voltage change rate corresponding to the same sampling time are combined to generate a joint feature vector, and then a joint feature sequence is formed according to the sampling time sequence. The joint feature sequence is input into a preset stage state encoding rule to obtain the stage state identifier sequence corresponding to each sampling time. The sampling positions where the state identifiers of adjacent sampling times in the stage state identifier sequence change are used as candidate boundary points. Based on the duration of the state before and after the candidate boundary point and the interval between the candidate boundary points, the candidate boundary points are filtered and merged to obtain the stage boundary point sequence. The switching process of power devices is divided into stages based on the aforementioned stage boundary point sequence.

4. The gate optocoupler current regulation method based on multi-objective complementary control according to claim 3, characterized in that, The process of filtering and merging candidate boundary points based on the duration of states before and after the candidate boundary point and the interval between candidate boundary points yields a sequence of stage boundary points, including: For each candidate boundary point, count the number of continuous sampling points of its adjacent state identifiers before and after it to obtain the forward duration and backward duration. The interval between adjacent candidate boundary points is calculated based on the preset sampling period and the sampling positions of adjacent candidate boundary points. When the forward duration or backward duration is less than the preset minimum duration, the corresponding candidate boundary point is removed. When the interval between adjacent candidate boundary points is less than the preset minimum stage interval, the adjacent candidate boundary points are merged. The candidate boundary points that are eliminated and merged are determined as the target boundary point sequence.

5. The gate optocoupler current regulation method based on multi-objective complementary control according to claim 4, characterized in that, The step of dividing the switching process of the power device into stages based on the stage boundary point sequence includes: Based on the target boundary point sequence, the switching process of the power device is divided into multiple continuous time intervals; For each time series interval, count the number of times each stage status identifier appears within that time series interval, and determine the stage status identifier that appears most frequently as the dominant status identifier for that time series interval. Based on the dominant state identifier corresponding to each time interval, a corresponding switching stage label is assigned to each time interval to obtain the stage division result of the power device switching process. The stage division result includes the gate initial charging stage, the Miller plateau regulation stage, and the conduction establishment stage.

6. The gate optocoupler current regulation method based on multi-objective complementary control according to claim 1, characterized in that, The process of establishing corresponding drive current envelope functions for different switching stages and adjusting the parameters of the drive current envelope function corresponding to the current switching stage based on the device voltage change rate includes: Based on the stage division results of the power device switching process, a corresponding drive current envelope function is configured for each switching stage, resulting in a set of stage drive current envelope functions. For each switching stage, the corresponding initial function parameters are determined. The initial function parameters include at least one of the current amplitude parameter, the change slope parameter, and the duration parameter. Calculate the function parameter correction amount for the current switching phase based on the device voltage change rate at the current sampling time; The driving current envelope function corresponding to the current switching stage is updated according to the function parameter correction amount to obtain the target driving current envelope function.

7. The gate optocoupler current regulation method based on multi-objective complementary control according to claim 6, characterized in that, The step of calculating the function parameter correction amount for the current switching phase based on the device voltage change rate corresponding to the current sampling time includes: Obtain the device voltage change rate at the current sampling moment and determine the reference value of the target device voltage change rate at the current switching stage; The device voltage change rate deviation value is calculated based on the difference between the device voltage change rate and the reference value of the target device voltage change rate. The device voltage change rate deviation value is input into a preset parameter mapping rule to obtain the function parameter correction amount for the current switching stage. The parameter mapping rule is used to establish the correspondence between the device voltage change rate deviation value and the adjustment range of the drive current envelope function parameter.

8. The gate optocoupler current regulation method based on multi-objective complementary control according to claim 6, characterized in that, Based on the stage division results of the power device switching process, a corresponding drive current envelope function is configured for each switching stage, resulting in a set of stage drive current envelope functions, including: For the initial gate charging phase, a monotonically increasing rising drive current envelope function is configured; For the Miller platform control phase, a limited-amplitude drive current envelope function is configured; For the conduction setup phase, a monotonically decreasing decaying drive current envelope function is configured; The drive current envelope functions corresponding to each switching stage are combined in stage order to obtain the stage drive current envelope function set.

9. The gate optocoupler current regulation method based on multi-objective complementary control according to claim 1, characterized in that, The step of generating a target gate drive current based on the parameter-corrected drive current envelope function, and adjusting the output drive current of the gate optocoupler according to the target gate drive current, includes: Based on the target drive current envelope function corresponding to the current switching stage, the target gate drive current value corresponding to each sampling time is calculated according to the sampling time sequence to generate the target drive current sequence. The target drive current sequence is converted into a corresponding optocoupler output regulation control quantity; The output drive current of the gate optocoupler is dynamically adjusted according to the optocoupler output adjustment control quantity corresponding to each sampling time.

10. A gate optocoupler current regulation system based on multi-objective complementary control, used to implement the gate optocoupler current regulation method based on multi-objective complementary control as described in any one of claims 1-9, characterized in that, The system includes a voltage acquisition module, a rate of change calculation module, a stage division module, an envelope function generation module, a parameter correction module, and a drive adjustment module, wherein: The voltage acquisition module is used to acquire the gate voltage and the voltage across the power device during the switching process of the power device. The rate of change calculation module is used to calculate the gate voltage rate of change based on the gate voltage, and to calculate the device voltage rate of change based on the voltage across the power device. The stage division module is used to divide the switching process of the power device into stages based on the gate voltage change rate and the device voltage change rate, and obtain stage division results for different switching stages. The envelope function generation module is used to establish corresponding drive current envelope functions for different switching stages, thereby obtaining a set of stage drive current envelope functions. The parameter correction module is used to correct the parameters of the drive current envelope function corresponding to the current switching stage according to the device voltage change rate, so as to obtain the target drive current envelope function. The drive adjustment module is used to generate a target gate drive current based on the parameter-corrected drive current envelope function, and adjust the output drive current of the gate optocoupler according to the target gate drive current.

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