A method and system for intelligent control of excimer lamp power supply

Abstract

This invention belongs to the technical field of power supply control, specifically relating to an intelligent control method and system for excimer lamp power supplies, comprising the following steps: S1, acquiring the real-time output voltage, output current, and DC bus voltage of the phase-shifted full-bridge excimer lamp; using an extended Kalman filter model, estimating the equivalent complex impedance amplitude, phase angle, and phase angle change rate of the excimer lamp in the next switching cycle based on the voltage and current sampling values ​​over multiple consecutive switching cycles; S2, calculating the basic phase shift angle using a proportional-integral controller based on the deviation between the target output power and the real-time power, wherein the gain of the proportional-integral controller is determined based on the phase angle change rate. This invention improves the accuracy of power control and the ability to suppress load disturbances and voltage fluctuations, ensuring stable output power, reducing switching losses, ensuring rapid and successful lamp lighting, and achieving a smooth transition to closed-loop control.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of power supply control, and particularly relates to an intelligent control method and system for a power supply of an excimer lamp. BACKGROUND

[0002] The power supply for powering the excimer lamp usually adopts a high-frequency alternating current form, wherein the phase-shifted full-bridge (PSFB) excimer lamp is a typical gas discharge load, and the equivalent impedance of the excimer lamp will change dramatically before and after lighting and during the working process. In the starting stage, the lamp tube presents a capacitive high impedance state; after the plasma is formed, it changes into a resistive low impedance state.

[0003] The existing control is difficult to adapt to wide-range impedance changes, and problems such as slow dynamic response, large power overshoot and even system oscillation are prone to occur in the power regulation process, which cannot meet the requirements of rapidity and stability at the same time. Therefore, for the lighting starting process, an open-loop sweep frequency or a high-voltage pulse is usually used to find the resonance point and break down the gas, but the reliability of this method is not high, and there is no judgment on whether the lighting is successful or not, which may lead to lighting failure or impact on the components. Most of these methods are based on a simplified load model, and the equivalent complex impedance information of the excimer lamp at different operating points cannot be obtained in real time, which leads to limited compensation accuracy. In addition, when the load impedance changes or is light, the lagging bridge arm of the phase-shifted full-bridge may lose the zero-voltage opening condition, resulting in increased switching loss, which is also a problem to be solved in the prior art. SUMMARY

[0004] The application provides an intelligent control method and system for a power supply of an excimer lamp to solve the technical problems of poor power regulation, unreliable lighting starting, low compensation accuracy and increased switching loss of the power supply of the excimer lamp due to dramatic changes in the load impedance in the prior art.

[0005] In a first aspect, the application provides an intelligent control method for a power supply of an excimer lamp, comprising the following steps:

[0006] S1, obtaining real-time output voltage, output current of the excimer lamp and DC bus voltage of the phase-shifted full-bridge; using an extended Kalman filter model, estimating the equivalent complex impedance amplitude, phase angle and phase angle change rate of the excimer lamp in the next switching cycle according to the voltage and current sampling values in the continuous multiple switching cycles;

[0007] S2, calculating the basic phase shift angle through a proportional-integral controller according to the deviation of the target output power and the real-time power, wherein the gain of the proportional-integral controller is determined according to the phase angle change rate; superimposing the basic phase shift angle, the nonlinear feedforward compensation based on the equivalent complex impedance amplitude and the phase angle of the excimer lamp, and the voltage feedforward compensation based on the DC bus voltage to generate a target phase shift angle;

[0008] S3, when the equivalent complex impedance amplitude of the excimer lamp is greater than the light load threshold and the DC bus voltage fluctuation is less than the stability threshold, determining a duty cycle adjustment amount from the equivalent complex impedance amplitude of the excimer lamp and the DC bus voltage change rate, and using the duty cycle adjustment amount to asymmetrically drive the lagging bridge arm of the phase-shifted full-bridge;

[0009] S4, in the start-up lighting stage, driving the phase-shifted full-bridge in a sweep frequency manner, and monitoring the cross-correlation coefficient of the voltage and current and the third harmonic amplitude of the voltage; when the absolute value of the cross-correlation coefficient reaches a peak value and the third harmonic amplitude exceeds a firing threshold, locking the current frequency and applying a maximum phase shift angle for firing; when the equivalent complex impedance amplitude of the excimer lamp is stable below the plasma formation threshold, switching to closed-loop power control and driving the phase-shifted full-bridge with a target phase shift angle.

[0010] Further, an extended Kalman filter model is used to estimate the equivalent complex impedance amplitude, phase angle and phase angle change rate of the excimer lamp in the next switching period according to the voltage and current sampling values in the continuous multiple switching periods, including:

[0011] A state space model is constructed with the equivalent complex impedance amplitude, phase angle and phase angle change rate of the excimer lamp as state variables;

[0012] The voltage and current fundamental components are extracted by fast Fourier transform to calculate the complex impedance measurement value of the current period;

[0013] The extended Kalman filter algorithm is used to update and output the state variable estimation value of the next period by combining state prediction and the complex impedance measurement value of the current period.

[0014] Further, the duty cycle adjustment amount is determined from the equivalent complex impedance amplitude of the excimer lamp and the DC bus voltage change rate, including:

[0015] Setting high and low proportional integral gain parameters and a phase angle change rate stability threshold;

[0016] When the absolute value of the phase angle change rate is less than the stability threshold, proportional integral control is performed with high gain parameters;

[0017] When the absolute value of the phase angle change rate is greater than or equal to the stability threshold, proportional integral control is performed with low gain parameters.

[0018] Further, in S2, the target phase shift angle includes a nonlinear feedforward compensation angle and a voltage feedforward compensation angle, and the nonlinear feedforward compensation angle is obtained by querying a two-dimensional lookup table with the equivalent complex impedance amplitude and phase angle of the excimer lamp as inputs;

[0019] The voltage feedforward compensation angle is directly proportional to the deviation between the real-time value and the nominal value of the DC bus voltage.

[0020] Further, the lagging bridge arm of the phase-shifted full-bridge is asymmetrically driven by the duty cycle adjustment amount, including:

[0021] When the equivalent complex impedance amplitude of the excimer lamp is greater than the light load threshold and the absolute value of the DC bus voltage change rate is less than the stability threshold, the asymmetric driving is enabled;

[0022] The duty cycle adjustment amount is calculated according to the difference between the equivalent complex impedance amplitude of the excimer lamp and the light load threshold and the DC bus voltage change rate;

[0023] The driving duty cycles of the upper and lower switch tubes of the lagging bridge arm are respectively set to 0.5 plus the duty cycle adjustment amount and 0.5 minus the duty cycle adjustment amount.

[0024] Further, when the equivalent complex impedance amplitude of the excimer lamp is stable below the plasma formation threshold, the closed-loop power control is switched to, including:

[0025] After ignition, the equivalent complex impedance amplitude of the excimer lamp is continuously monitored;

[0026] When the equivalent complex impedance amplitude of the excimer lamp is maintained below the preset plasma formation threshold for more than the preset stable time, the driving mode is switched from the ignition mode to the closed-loop power control mode.

[0027] In a second aspect, the present application provides an intelligent control system for an excimer lamp power supply, including the following modules:

[0028] An estimation module is used to obtain the real-time output voltage, output current of the excimer lamp and the DC bus voltage of the phase-shifted full-bridge; an extended Kalman filter model is used to estimate the equivalent complex impedance amplitude, phase angle and phase angle change rate of the excimer lamp in the next switching period according to the voltage and current sampling values in continuous multiple switching periods;

[0029] A phase-shift angle determination module is used to calculate the basic phase-shift angle through a proportional-integral controller according to the deviation between the target output power and the real-time power, wherein the gain of the proportional-integral controller is determined according to the phase angle change rate; the basic phase-shift angle, the nonlinear feedforward compensation based on the equivalent complex impedance amplitude and the phase angle, and the voltage feedforward compensation based on the DC bus voltage are superimposed to generate the target phase-shift angle;

[0030] An adjustment module is used to determine the duty cycle adjustment amount from the equivalent complex impedance amplitude of the excimer lamp and the DC bus voltage change rate when the equivalent complex impedance amplitude of the excimer lamp is greater than the light load threshold and the DC bus voltage fluctuation is less than the stability threshold, and the lagging bridge arm of the phase-shifted full-bridge is asymmetrically driven by the duty cycle adjustment amount;

[0031] The drive module is used to drive the phase-shifted full bridge in a frequency sweep manner during the lamp start-up phase, and monitor the cross-correlation coefficient of voltage and current and the amplitude of the third harmonic of voltage. When the absolute value of the cross-correlation coefficient reaches the peak value and the amplitude of the third harmonic exceeds the ignition threshold, the current frequency is locked and the maximum phase shift angle is applied for ignition. When the amplitude of the equivalent complex impedance of the excimer lamp stabilizes below the plasma formation threshold, it switches to closed-loop power control and drives the phase-shifted full bridge with the target phase shift angle.

[0032] Furthermore, using an extended Kalman filter model, based on voltage and current sampling values ​​over multiple consecutive switching cycles, the equivalent complex impedance amplitude, phase angle, and phase angle change rate of the excimer lamp in the next switching cycle are estimated, including:

[0033] A state-space model is constructed with the equivalent complex impedance amplitude, phase angle, and phase angle change rate of the excimer lamp as state variables.

[0034] The fundamental components of voltage and current are extracted by fast Fourier transform, and the complex impedance measurement value of the current cycle is calculated.

[0035] An extended Kalman filter algorithm is used, which combines state prediction with the complex impedance measurement of the current cycle to update and output the estimated state variables for the next cycle.

[0036] Furthermore, the duty cycle adjustment is determined by the amplitude of the excimer lamp's equivalent complex impedance and the rate of change of the DC bus voltage, including:

[0037] Set the proportional-integral gain parameters and the phase angle change rate stability threshold for both high and low sets;

[0038] When the absolute value of the phase angle change rate is less than the stability threshold, proportional-integral control is performed using a high-gain parameter.

[0039] When the absolute value of the phase angle change rate is greater than or equal to the stability threshold, proportional-integral control is performed using a low gain parameter.

[0040] Furthermore, the target phase shift angle includes the nonlinear feedforward compensation angle and the voltage feedforward compensation angle. The nonlinear feedforward compensation angle is obtained by querying a two-dimensional lookup table with the equivalent complex impedance amplitude and phase angle of the excimer lamp as input.

[0041] The voltage feedforward compensation angle is proportional to the deviation between the real-time value and the nominal value of the DC bus voltage.

[0042] The beneficial effects are as follows: Compared with existing technologies, this invention, by employing an extended Kalman filter model, can identify the amplitude, phase angle, and rate of change of the equivalent complex impedance of the excimer lamp, thereby obtaining the real-time status of the load. Combined with nonlinear feedforward based on complex impedance and bus voltage feedforward compensation, the accuracy of power control and the ability to suppress load disturbances and voltage fluctuations are improved, ensuring stable output power. Furthermore, the asymmetric drive strategy can effectively extend the zero-voltage turn-on range of the lagging arm under light load conditions, reducing switching losses. During the lamp start-up phase, by monitoring the voltage-current cross-correlation coefficient and the third harmonic of the voltage, the rapid and successful lamp-starting process is ensured, achieving a smooth transition to closed-loop control. Attached Figure Description

[0043] Figure 1 The flowchart shows the intelligent control method for excimer lamp power supply. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] An embodiment of the intelligent power supply control method for excimer lamps provided by this invention:

[0046] like Figure 1 As shown, the intelligent control method for excimer lamp power supply includes the following steps:

[0047] S1 acquires the real-time output voltage and current of the excimer lamp, as well as the DC bus voltage of the phase-shifted full-bridge; using an extended Kalman filter model, based on the voltage and current sampling values ​​within multiple consecutive switching cycles, it estimates the amplitude, phase angle, and phase angle change rate of the excimer lamp in the next switching cycle.

[0048] A phase-shifted full-bridge converter is a type of DC-DC converter consisting of four switching transistors arranged in two pairs, or two arms. One arm is called the leading arm, and the other is called the lagging arm. By controlling the phase difference, or phase shift angle, between the drive signals of the two arms, the energy transmitted to the output is adjusted, thereby controlling the output voltage or power. Excimer lamps require hundreds or even thousands of watts of power. This invention uses a phase-shifted full-bridge converter to boost the low-voltage DC input to the high voltage required by the lamp, while simultaneously achieving electrical isolation between the input and output. Data acquisition is preferably achieved by setting Hall voltage and current sensors at the output of the excimer lamp and a voltage sensor on the DC bus. The analog-to-digital converter module inside the digital signal processor synchronously samples the analog signals output by the sensors at a sampling rate higher than the switching frequency, converting the acquired voltage and current data into digital quantities and storing them in memory.

[0049] A state-space equation is established with the equivalent complex impedance amplitude, phase angle, and phase angle change rate of the excimer lamp as state variables. Real-time acquired digital voltage and current values ​​are used as observations. First, a prediction step is performed to predict the prior state value at the current moment based on the posterior state estimate of the previous moment and the system model. Then, an update step is performed to calculate the Kalman gain using the deviation between the actual voltage and current observations and the predicted observations at the current moment, and to correct the prior state estimate, thereby obtaining the optimized posterior estimate of the complex impedance parameters for the next cycle.

[0050] In an optional embodiment, an extended Kalman filter model is used to estimate the magnitude, phase angle, and rate of change of the excimer lamp equivalent complex impedance for the next switching cycle based on voltage and current sampling values ​​over multiple consecutive switching cycles, including:

[0051] A state-space model is constructed with the equivalent complex impedance amplitude, phase angle, and phase angle change rate of the excimer lamp as state variables.

[0052] The fundamental components of voltage and current are extracted by fast Fourier transform, and the complex impedance measurement value of the current cycle is calculated.

[0053] An extended Kalman filter algorithm is used, which combines state prediction with the complex impedance measurement of the current cycle to update and output the estimated state variables for the next cycle.

[0054] The state vector of the state-space model consists of the excimer lamp equivalent complex impedance amplitude, phase angle, and phase angle change rate. This model is used to predict the values ​​of these three state quantities after one switching cycle. To provide the model with real-time measurement data, the output voltage and current are sampled at high speed during each switching cycle, for example, 256 points per cycle at a switching frequency of 100 kHz. Then, the fundamental amplitude and phase of the voltage and current are calculated using a fast Fourier transform algorithm, thereby obtaining the measured values ​​of the excimer lamp equivalent complex impedance amplitude and phase angle for the current cycle.

[0055] The Extended Kalman Filter (EKF) algorithm is an optimal estimation algorithm for nonlinear systems, consisting of two steps: prediction and update. In the prediction step, the state space model and the optimal estimate from the previous cycle are used to predict the state for the current cycle. In the update step, the predicted value is compared with the actual measured value for the current cycle obtained through a Fast Fourier Transform (FFT), and the error between the two is calculated. This error is weighted using the Kalman gain to correct the predicted value, resulting in a more accurate optimal estimate of the state for the current cycle. For example, if the predicted phase angle is 25.5 degrees and the measured value is 25.1 degrees, the filtering algorithm will output an estimate between the two, such as 25.3 degrees, and simultaneously output the predicted value for the next cycle, thus achieving tracking of complex impedance parameters and noise suppression.

[0056] The state vector of the extended Kalman filter model is [excimer lamp equivalent complex impedance amplitude, phase angle, phase angle change rate], while the observation vector of the extended Kalman filter model consists of the real-time output voltage and current values ​​of the excimer lamp obtained by direct sampling.

[0057] In one embodiment, the state vector It contains three core parameters to be estimated. ,in, The equivalent complex impedance amplitude of the excimer lamp (unit: ohms). Phase angle (unit: rad) Phase angle change rate (unit: rad / s). Observation vector. The equivalent complex impedance is obtained by sampling and calculating the output voltage v(t) and current i(t) of the collimator lamp. Specifically, within one or more switching cycles, the fundamental components of the voltage and current are extracted by Fast Fourier Transform or other digital signal processing methods, thereby calculating the amplitude and phase angle of the equivalent complex impedance at the current moment.

[0058] ,in, , This represents the phase difference between the fundamental voltage and current frequencies.

[0059] The extended Kalman filter algorithm consists of two main steps: prediction and update. Let the sampling period be Δt, preferably Δt = 100 μs.

[0060] The prediction process is as follows:

[0061] State transition equation Predict the state at the next moment based on the physical model.

[0062]

[0063]

[0064]

[0065] Predicting covariance matrix :

[0066] in, Q is the Jacobian matrix of the state transition function f, and Q is the process noise covariance matrix.

[0067] The process noise covariance Q reflects the uncertainty in the predictions of the extended Kalman filter model and is a diagonal matrix. Preferably: This indicates that within one Δt period, the standard deviation of the excimer lamp equivalent complex impedance amplitude is estimated to be approximately 0.1 ohms, the standard deviation of the phase angle is estimated to be approximately 0.01 rad, and the standard deviation of the phase angle change rate is estimated to be approximately 0.05 rad / s.

[0068] The update process is as follows:

[0069] Observation equations Mapping the predicted state to the observation space, .

[0070] Calculate Kalman gain : .

[0071] in, R is the Jacobian matrix of the observation function h, and R is the measurement noise covariance matrix.

[0072] The measurement noise covariance R reflects the measurement error introduced by the sensor and signal processing, and is a diagonal matrix. Preferably This indicates that the standard deviation of the measurement of the equivalent complex impedance amplitude of the excimer lamp is 0.2 ohms, and the standard deviation of the measurement of the phase angle is 0.02 rad (approximately 1.15 degrees).

[0073] Update state estimation .

[0074] Update covariance matrix .

[0075] S2, based on the deviation between the target output power and the real-time power, the base phase shift angle is calculated by a proportional-integral controller, wherein the gain of the proportional-integral controller is determined according to the phase angle change rate; the base phase shift angle, the nonlinear feedforward compensation based on the equivalent complex impedance amplitude and phase angle of the excimer lamp, and the voltage feedforward compensation based on the DC bus voltage are superimposed to generate the target phase shift angle.

[0076] The real-time output voltage and current values ​​are multiplied and integrated over one switching cycle to obtain the real-time output power. This power deviation is then subtracted from the set target power value. This deviation is input to a proportional-integral (PI) controller, which calculates the base phase shift angle based on the proportional and integral terms of the deviation. The formula for the PI controller is as follows: ,in, It's a power deviation. It is proportional gain. It is the integral gain.

[0077] The proportional-integral controller consults a preset gain scheduling table and adjusts the proportional gain and integral gain according to the absolute value of the phase angle change rate output by the extended Kalman filter algorithm. For example, when the phase angle change rate is large, the gain is automatically reduced to enhance stability, and vice versa to increase the gain to improve the response speed.

[0078] In one embodiment, the gain scheduling table is specifically as follows:

[0079] 1. In the transient / unstable region, |dθ / dt|>10000, the proportional gain is 0.05 and the integral gain is 1;

[0080] 2. In the dynamic adjustment region, 2000 < |dθ / dt| ≤ 10000, the proportional gain is 0.2, and the integral gain is 5.

[0081] 3. In the normal operating range, 500 < |dθ / dt| ≤ 2000, the proportional gain is 0.5, and the integral gain is 20.

[0082] 4. In the steady-state region, |dθ / dt|≤500, the proportional gain is 0.8, and the integral gain is 35.

[0083] Using the equivalent complex impedance amplitude and phase angle of the excimer lamp estimated by the extended Kalman filter algorithm as an index, a two-dimensional nonlinear feedforward compensation table that has been established in advance through offline simulation or experimental calibration is queried to obtain an impedance feedforward compensation angle.

[0084] In one embodiment, the two-dimensional nonlinear feedforward compensation table is shown in Table 1:

[0085] Table 1

[0086]

[0087] The difference between the real-time acquired DC bus voltage and the standard rated voltage is calculated, and the difference is multiplied by a voltage feedforward coefficient to obtain the voltage feedforward compensation angle. The base phase shift angle, impedance feedforward compensation angle, and voltage feedforward compensation angle output by the proportional-integral controller are algebraically summed to synthesize the target phase shift angle.

[0088] S3, when the equivalent complex impedance amplitude of the excimer lamp is greater than the light load threshold and the DC bus voltage fluctuation is less than the stable threshold, the duty cycle adjustment amount is determined by the equivalent complex impedance amplitude of the excimer lamp and the DC bus voltage change rate, and the lagging bridge arm of the phase-shifted full bridge is asymmetrically driven using the duty cycle adjustment amount.

[0089] The proportional-integral controller continuously compares the amplitude of the excimer lamp's equivalent complex impedance with a preset light-load threshold, such as five times the rated load impedance, and calculates the differential value of the DC bus voltage, i.e., the rate of change. When the amplitude of the excimer lamp's equivalent complex impedance is higher than the light-load threshold and the absolute value of the voltage change rate is lower than the stability threshold of 0.05V / ms, the proportional-integral controller starts asymmetric drive. Based on the current amplitude of the excimer lamp's equivalent complex impedance and the rate of change of the bus voltage, a duty cycle adjustment amount, such as 5%, is determined by consulting another two-dimensional adjustment table. Then, the drive pulse width of the upper MOSFET of the hysteresis bridge arm is subtracted from the adjustment amount, and the drive pulse width of the lower MOSFET is increased by the adjustment amount to ensure zero-voltage turn-on under light load.

[0090] Asymmetric drive is used to improve power efficiency under light load conditions. Its activation condition ensures that it is activated only when the system is stable and indeed under light load. For example, the light load threshold is set to 300 ohms, and the DC bus voltage change rate stability threshold is 1V / ms. When the equivalent complex impedance amplitude of the current lamp excimer is detected to be 350 ohms, and the bus voltage change rate is only 0.4V / ms, both conditions are met simultaneously, and the proportional-integral controller starts the asymmetric drive mode.

[0091] In an optional embodiment, the duty cycle adjustment is determined by the amplitude of the excimer lamp's equivalent complex impedance and the rate of change of the DC bus voltage, including:

[0092] Set the proportional-integral gain parameters and the phase angle change rate stability threshold for both high and low sets;

[0093] When the absolute value of the phase angle change rate is less than the stability threshold, proportional-integral control is performed using a high-gain parameter.

[0094] When the absolute value of the phase angle change rate is greater than or equal to the stability threshold, proportional-integral control is performed using a low gain parameter.

[0095] Two sets of proportional-integral (PI) parameters are preset. One set is a high-gain parameter with a proportional gain of 0.9 and an integral gain of 600, used to track the power setting when the lamp is operating stably. The other set is a low-gain parameter with a proportional gain of 0.3 and an integral gain of 150, used for transient processes with drastic changes in lamp status to ensure system stability and avoid overshoot and oscillation.

[0096] Simultaneously, a stable threshold for the phase angle change rate is set, for example, 0.2 degrees per switching cycle. During operation, the phase angle change rate estimated by the Kalman filter is monitored in real time. When its absolute value is less than 0.2 degrees per cycle, it indicates that the plasma discharge is stable, and the proportional-integral controller automatically selects high-gain parameters. Conversely, during transient processes such as lamp ignition or load abrupt changes, the absolute value of the phase angle change rate will increase sharply and exceed 0.2 degrees per cycle. In this case, the proportional-integral controller automatically switches to low-gain parameters, sacrificing some response speed in exchange for the system remaining stable under large disturbances.

[0097] In an optional embodiment, asymmetric driving is employed on the hysteresis arm of the phase-shifted full-bridge using a duty cycle adjustment, including:

[0098] When the amplitude of the equivalent complex impedance of the excimer lamp is greater than the light load threshold and the absolute value of the DC bus voltage change rate is less than the stability threshold, asymmetric drive is enabled.

[0099] The duty cycle adjustment is calculated based on the difference between the equivalent complex impedance amplitude of the excimer lamp and the light load threshold, as well as the DC bus voltage change rate.

[0100] The drive duty cycles of the upper and lower switching transistors of the lagging bridge arm are set to 0.5 plus the duty cycle adjustment amount and 0.5 minus the duty cycle adjustment amount, respectively.

[0101] For example, a light load threshold of 300 ohms and a DC bus voltage change rate stability threshold of 1V / ms are set. When the equivalent complex impedance amplitude of the current lamp is detected to be 350 ohms and the bus voltage change rate is only 0.4V / ms, both conditions are met simultaneously, and the proportional-integral controller (PIC) will activate the asymmetric drive mode. After activation, the PIC calculates a duty cycle adjustment, the magnitude of which is related to the load severity. For example, the adjustment can be a proportional coefficient multiplied by the difference between the equivalent complex impedance amplitude of the excimer lamp and the light load threshold. If the proportional coefficient is 0.02%, the duty cycle adjustment in the above example is 0.01. Subsequently, the PIC adjusts the drive duty cycle of the upper MOSFET in the lag arm from the standard 0.5 to 0.51, and simultaneously adjusts the drive duty cycle of the lower MOSFET from 0.5 to 0.49. The duty cycle changes the voltage waveform at the midpoint of the arm, which helps to achieve zero-voltage turn-on of the switching transistor under light load.

[0102] S4, during the lamp-starting phase, drives the phase-shifting full bridge in a frequency sweep manner and monitors the cross-correlation coefficient of voltage and current and the amplitude of the third harmonic of voltage; when the absolute value of the cross-correlation coefficient reaches the peak value and the amplitude of the third harmonic exceeds the ignition threshold, the current frequency is locked and the maximum phase shift angle is applied for ignition; when the amplitude of the excimer lamp equivalent complex impedance stabilizes below the plasma formation threshold, it switches to closed-loop power control and drives the phase-shifting full bridge with the target phase shift angle.

[0103] At the start of ignition, the proportional-integral controller drives the phase-shifting full-bridge with a fixed small phase-shift angle, and linearly or stepwise scans the switching frequency from high to low, for example, from 100 kHz to 60 kHz. During this process, the cross-correlation coefficient is calculated in real time by convolution operation on the voltage and current sampling sequences, and the third harmonic amplitude of the voltage signal is calculated by fast Fourier transform. When the absolute value of the cross-correlation coefficient reaches an inflection point, i.e., the peak value is reached, and the third harmonic amplitude is greater than the preset ignition threshold, for example, 10% of the rated voltage, the frequency sweep is immediately stopped, the current frequency is taken as the optimal ignition frequency, and the phase-shift angle command is immediately set to the maximum value, for example, 175 degrees, to break down the lamp gas with high energy. After ignition, the proportional-integral controller continuously monitors the equivalent complex impedance amplitude of the excimer lamp through Kalman filtering. When its value drops rapidly from the kiloohm level and stabilizes below the plasma formation threshold of 100 ohms for more than 20 ms, the ignition is determined to be successful, and the system automatically switches from the start-up mode to the closed-loop power control mode.

[0104] In an optional embodiment, the target phase shift angle includes a nonlinear feedforward compensation angle and a voltage feedforward compensation angle, wherein the nonlinear feedforward compensation angle is obtained by querying a two-dimensional lookup table with the equivalent complex impedance amplitude and phase angle of the excimer lamp as input.

[0105] The voltage feedforward compensation angle is proportional to the deviation between the real-time value and the nominal value of the DC bus voltage.

[0106] The base phase shift angle is calculated by the traditional proportional-integral (PI) controller based on power error. The nonlinear feedforward compensation angle is used to overcome the inherent nonlinearity of the system; this relationship also varies with the load impedance state. Through offline experiments or simulations, a two-dimensional lookup table is established with the equivalent complex impedance amplitude of the excimer lamp as the horizontal axis and the complex impedance phase angle as the vertical axis. The table stores the compensation phase shift angles required to achieve unit power output at different impedance points. During operation, the PI controller, based on the real-time estimated amplitude and phase angle of the excimer lamp's equivalent impedance (e.g., amplitude 150 ohms, phase angle -10 degrees), looks up a corresponding compensation angle (e.g., 3.5 degrees) from the table and adds it to the base phase shift angle. The voltage feedforward compensation angle is used to actively suppress the interference of DC bus voltage fluctuations on the output power. For example, setting the nominal bus voltage to 400 volts and the feedforward gain to 0.1 degrees per volt, if the real-time measured bus voltage drops to 390 volts, a 10-volt voltage difference is generated, and the calculated voltage feedforward compensation angle is 1 degree. The proportional-integral controller adds these three factors together: the nonlinear feedforward compensation angle obtained by looking up the table from the basic phase shift angle output by the proportional-integral controller, and the calculated voltage feedforward compensation angle, to obtain the final total phase shift angle applied to the power inverter.

[0107] In an optional embodiment, when the equivalent complex impedance amplitude of the excimer lamp stabilizes below the plasma formation threshold, switching to closed-loop power control includes:

[0108] After ignition, continuously monitor the amplitude of the excimer lamp's equivalent complex impedance;

[0109] When the equivalent complex impedance amplitude of the excimer lamp remains below the preset plasma formation threshold for more than a preset stabilization time, the driving mode will be switched from ignition mode to closed-loop power control mode.

[0110] After successful ignition, the proportional-integral controller remains in open-loop maximum power output mode to consolidate plasma formation. During this period, the equivalent complex impedance amplitude of the excimer lamp is continuously calculated using fast Fourier transform. When unlit, the lamp exhibits a high-impedance capacitive load, with an equivalent excimer lamp impedance amplitude reaching several thousand ohms. However, once a stable plasma glow discharge is established, it transforms into a low-impedance purely resistive or weakly inductive load.

[0111] To determine whether plasma has been stably formed, two parameters are set: a plasma formation threshold and a stabilization time. For example, the impedance threshold is set to 200 ohms, and the stabilization time is set to 100 ms. After ignition, the proportional-integral controller continuously compares the real-time calculated excimer lamp equivalent impedance amplitude of the lamp with 200 ohms. When the measured excimer lamp equivalent impedance amplitude first drops below 200 ohms, an internal timer starts. If the excimer lamp equivalent impedance amplitude remains below 200 ohms for the next 100 ms without a significant rebound, the plasma is considered fully established and stable. At this point, the proportional-integral controller automatically switches the drive mode from fixed maximum power ignition.

[0112] The present invention provides an intelligent control system for excimer lamp power supply, comprising the following modules:

[0113] The estimation module is used to obtain the real-time output voltage and current of the excimer lamp and the DC bus voltage of the phase-shifted full bridge; it adopts an extended Kalman filter model to estimate the amplitude of the equivalent complex impedance of the excimer lamp, the phase angle and the rate of change of the phase angle in the next switching cycle based on the voltage and current sampling values ​​in multiple consecutive switching cycles.

[0114] The phase shift angle determination module is used to calculate the basic phase shift angle based on the deviation between the target output power and the real-time power through a proportional-integral controller. The gain of the proportional-integral controller is determined based on the phase angle change rate. The basic phase shift angle, the nonlinear feedforward compensation based on the amplitude and phase angle of the excimer lamp equivalent complex impedance, and the voltage feedforward compensation based on the DC bus voltage are superimposed to generate the target phase shift angle.

[0115] The adjustment module is used to determine the duty cycle adjustment amount by the equivalent complex impedance amplitude of the excimer lamp and the rate of change of the DC bus voltage when the amplitude of the equivalent complex impedance of the excimer lamp is greater than the light load threshold and the DC bus voltage fluctuation is less than the stable threshold. The duty cycle adjustment amount is used to apply asymmetric drive to the hysteresis arm of the phase-shifted full bridge.

[0116] The drive module is used to drive the phase-shifted full bridge in a frequency sweep manner during the lamp start-up phase, and monitor the cross-correlation coefficient of voltage and current and the amplitude of the third harmonic of voltage. When the absolute value of the cross-correlation coefficient reaches the peak value and the amplitude of the third harmonic exceeds the ignition threshold, the current frequency is locked and the maximum phase shift angle is applied for ignition. When the amplitude of the equivalent complex impedance of the excimer lamp stabilizes below the plasma formation threshold, it switches to closed-loop power control and drives the phase-shifted full bridge with the target phase shift angle.

[0117] The above are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. An intelligent control method for an excimer lamp power supply, characterized by, The method comprises the following steps: S1, acquiring real-time output voltage, output current of the excimer lamp and DC bus voltage of the phase-shifted full bridge; adopting an extended Kalman filter model, estimating the equivalent complex impedance amplitude, phase angle and phase angle change rate of the excimer lamp in the next switching period according to the voltage and current sampling values in continuous multiple switching periods; S2, calculating the basic phase shift angle through a proportional-integral controller according to the deviation between the target output power and the real-time power, wherein the gain of the proportional-integral controller is determined according to the phase angle change rate; superimposing the basic phase shift angle, the nonlinear feedforward compensation based on the equivalent complex impedance amplitude and the phase angle of the excimer lamp and the voltage feedforward compensation based on the DC bus voltage to generate the target phase shift angle; S3, when the equivalent complex impedance amplitude of the excimer lamp is greater than the light load threshold and the DC bus voltage fluctuation is less than the stable threshold, determining the duty cycle adjustment amount according to the equivalent complex impedance amplitude of the excimer lamp and the DC bus voltage change rate, and using the duty cycle adjustment amount to adopt asymmetric driving for the lagging bridge arm of the phase-shifted full bridge; S4, in the start-up lighting stage, driving the phase-shifted full bridge in a sweep frequency manner, and monitoring the cross-correlation coefficient of voltage and current and the third harmonic amplitude of voltage; when the absolute value of the cross-correlation coefficient reaches the peak value and the third harmonic amplitude exceeds the ignition threshold, locking the current frequency and applying the maximum phase shift angle to ignite; when the equivalent complex impedance amplitude of the excimer lamp is stable below the plasma formation threshold, switching to closed-loop power control and driving the phase-shifted full bridge using the target phase shift angle.

2. The method of claim 1, wherein the method further comprises: The extended Kalman filter model is adopted to estimate the equivalent complex impedance amplitude, phase angle and phase angle change rate of the excimer lamp in the next switching period according to the voltage and current sampling values in continuous multiple switching periods, which comprises: a state space model is constructed with the equivalent complex impedance amplitude, phase angle and phase angle change rate of the excimer lamp as state variables; the voltage and current fundamental components are extracted through fast Fourier transform to calculate the complex impedance measurement value of the current period; the extended Kalman filter algorithm is adopted to update and output the state variable estimation value of the next period by combining state prediction and the complex impedance measurement value of the current period.

3. The method of claim 1, wherein the method further comprises: The duty cycle adjustment amount is determined according to the equivalent complex impedance amplitude of the excimer lamp and the DC bus voltage change rate, which comprises: setting high and low two groups of proportional-integral gain parameters and phase angle change rate stable threshold; when the absolute value of the phase angle change rate is less than the stable threshold, high gain parameters are used for proportional-integral control; when the absolute value of the phase angle change rate is greater than or equal to the stable threshold, low gain parameters are used for proportional-integral control.

4. The method of claim 1, wherein the method further comprises: In S2, the target phase shift angle comprises a nonlinear feedforward compensation angle and a voltage feedforward compensation angle, and the nonlinear feedforward compensation angle is obtained by querying a two-dimensional lookup table with the equivalent complex impedance amplitude and the phase angle of the excimer lamp as inputs; the voltage feedforward compensation angle is proportional to the deviation between the real-time value and the nominal value of the DC bus voltage.

5. The method of claim 1, wherein the method further comprises: The asymmetric driving is used for the lagging bridge arm of the phase-shifted full bridge by using the duty cycle adjustment amount, which comprises: when the equivalent complex impedance amplitude of the excimer lamp is greater than the light load threshold and the absolute value of the DC bus voltage change rate is less than the stable threshold, the asymmetric driving is enabled; the duty cycle adjustment amount is calculated according to the difference between the equivalent complex impedance amplitude of the excimer lamp and the light load threshold and the DC bus voltage change rate; The drive duty cycles of the upper and lower switch tubes of the lagging bridge arm are respectively set as 0.5 plus a duty cycle adjustment amount and 0.5 minus the duty cycle adjustment amount.

6. The method of claim 1-5, wherein the method further comprises: When the equivalent complex impedance amplitude of the excimer lamp is stable below the plasma formation threshold, switching to closed-loop power control, including: After ignition, continuously monitor the equivalent complex impedance amplitude of the excimer lamp; When the equivalent complex impedance amplitude of the excimer lamp is maintained below the preset plasma formation threshold for more than the preset stabilization time, switch the driving mode from the ignition mode to the closed-loop power control mode.

7. An intelligent control system for an excimer lamp power supply, characterized in that, Including the following modules: An estimation module is configured to obtain the real-time output voltage, output current of the excimer lamp and the DC bus voltage of the phase-shifted full-bridge; an extended Kalman filter model is used to estimate the equivalent complex impedance amplitude, phase angle and phase angle change rate of the excimer lamp in the next switching period according to the voltage and current sampling values in continuous multiple switching periods; A phase shift angle determination module is configured to calculate the basic phase shift angle by a proportional-integral controller according to the deviation between the target output power and the real-time power, wherein the gain of the proportional-integral controller is determined according to the phase angle change rate; the basic phase shift angle, the nonlinear feedforward compensation based on the equivalent complex impedance amplitude and the phase angle of the excimer lamp, and the voltage feedforward compensation based on the DC bus voltage are superimposed to generate the target phase shift angle; An adjustment module is configured to determine the duty cycle adjustment amount from the equivalent complex impedance amplitude of the excimer lamp and the DC bus voltage change rate when the equivalent complex impedance amplitude of the excimer lamp is greater than the light load threshold and the DC bus voltage fluctuation is less than the stabilization threshold, and to use the duty cycle adjustment amount to drive the lagging bridge arm of the phase-shifted full-bridge asymmetrically; A driving module is configured to drive the phase-shifted full-bridge in a sweep frequency manner in the starting ignition stage, and to monitor the cross-correlation coefficient of the voltage and current and the third harmonic amplitude of the voltage; when the absolute value of the cross-correlation coefficient reaches the peak value and the third harmonic amplitude exceeds the ignition threshold, the current frequency is locked and the maximum phase shift angle is applied for ignition; when the equivalent complex impedance amplitude of the excimer lamp is stable below the plasma formation threshold, switching to closed-loop power control, and using the target phase shift angle to drive the phase-shifted full-bridge.

8. The excimer lamp power supply intelligent control system of claim 7, wherein, An extended Kalman filter model is used to estimate the equivalent complex impedance amplitude, phase angle and phase angle change rate of the excimer lamp in the next switching period according to the voltage and current sampling values in continuous multiple switching periods, including: A state space model is constructed with the equivalent complex impedance amplitude, phase angle and phase angle change rate of the excimer lamp as state variables; The voltage and current fundamental components are extracted by fast Fourier transform to calculate the complex impedance measurement value of the current period; The extended Kalman filter algorithm is used to update and output the state variable estimation value of the next period by combining the state prediction and the complex impedance measurement value of the current period.

9. The excimer lamp power supply intelligent control system of claim 7, wherein, The duty cycle adjustment amount is determined from the equivalent complex impedance amplitude of the excimer lamp and the DC bus voltage change rate, including: High and low sets of proportional-integral gain parameters and phase angle change rate stabilization thresholds are set; When the absolute value of the phase angle change rate is less than the stabilization threshold, high gain parameters are used for proportional-integral control; When the absolute value of the phase angle change rate is greater than or equal to the stabilization threshold, low gain parameters are used for proportional-integral control.

10. The excimer lamp power supply intelligent control system of claim 7, wherein, The target phase shift angle comprises a nonlinear feedforward compensation angle and a voltage feedforward compensation angle, the nonlinear feedforward compensation angle is obtained by inquiring a two-dimensional lookup table with the equivalent complex impedance amplitude and phase angle of the excimer lamp as input; The voltage feedforward compensation angle is proportional to the deviation of the real-time value and the nominal value of the DC bus voltage.

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