Adaptive learning method of PFC circuit control duty ratio feedforward under different load conditions

Abstract

The invention discloses a self-adaptive learning method of PFC circuit control duty ratio feedforward under different load conditions, which comprises the following steps of: under different load conditions, firstly calculating input voltage and output voltage in the duty ratio feedforward, and then forming a self-adaptive learning table; and finally, the power supply system directly calls data in the adaptive learning table under different load conditions, so that the time for real-time sampling and then operation is saved, the control speed of a power supply output voltage loop is greatly improved, the output voltage is more stable, the stable output of the output power supply can be maintained, and the power supply reliability is improved. Stable and reliable power supply is provided for semiconductor equipment, and stability and reliability of a semiconductor supply chain are guaranteed.

Description

Technical Field

[0001] The present invention relates to an induction heating power supply device technology on semiconductor equipment, and in particular to an adaptive learning method for PFC circuit duty cycle feedforward control under different load conditions. Background Art

[0002] With the continuous development of semiconductor technology, semiconductor equipment has been widely used in the fields of electronics, information, and communications. The operation of semiconductor equipment is inseparable from high-quality power supply. Traditional DC power supplies cannot meet the fast load dynamic adjustment of module power supply required by semiconductor equipment.

[0003] Existing technology:

[0004] (1) Patent of Shenzhen Dianliang New Energy Technology Co., Ltd.: PFC circuit control method based on load current feedforward, discloses a PFC circuit control method based on load current feedforward, the steps are: based on the PFC circuit, obtain input current, input voltage, load current and dual bus voltage; calculate the difference between the dual bus voltage and the dual bus voltage reference value, the difference is the voltage loop input; the voltage loop input obtains the voltage loop output through the controller, and performs voltage loop deviation control; calculates the dual bus voltage difference, the difference is the balance loop difference; performs balance loop deviation control based on the balance loop difference to obtain the balance loop output; the load current is compensated and controlled by the current feedforward controller, and outputs the feedforward compensation value; calculates the difference between the balance loop output and the feedforward compensation value, and uses the difference between the voltage loop output and the difference as the current loop given; compares the current loop given with the input current to perform current loop deviation control to obtain the current loop output; obtains the driving signal for driving the PFC circuit based on the current loop output.

[0005] (2) Patent of Changzhou University: The totem pole PFC circuit control method based on dual feedforward average current is different from the control method of the present application and belongs to the field of power factor correction of switching power supply, and in particular, it relates to a totem pole PFC circuit control method based on dual feedforward average current, which includes the following steps: S1, the AC power supply outputs a DC voltage Uo after passing through the totem pole PFC; S2, the output DC voltage is compared with the reference value Uo_ref as the feedback value of the voltage outer loop, and is multiplied with the input voltage feedforward after being adjusted by the PI controller, and the product is used as the given value of the current inner loop; S3, the given value is subtracted from the input current iL to obtain an error value, and the error value is adjusted by the PI controller and added to the duty cycle feedforward to output the modulated signal wave of the output bit circuit; S4, the modulated signal wave is compared with the carrier wave to obtain the control signal of the high-frequency switch.

[0006] (3) Model predictive adaptive control method, system, equipment and medium for DC-DC converters of Gree Electric Appliances Co., Ltd. of Zhuhai: Belonging to the field of DC-DC converter control technology, it discloses a model predictive adaptive control method, system, equipment and medium for DC-DC converters. The method includes: obtaining the output voltage of the DC-DC converter at the current sampling moment in real time, and outputting a steady-state error based on the output voltage at the current sampling moment and the output reference voltage prediction; making an adaptive judgment based on the steady-state error and the output reference voltage prediction and generating a virtual reference voltage, and the virtual reference voltage is controlled by continuous set model prediction after hysteresis limiting to output a duty cycle; the duty cycle is modulated by pulse width to output a PWM pulse wave, thereby controlling the power switch in the DC-DC converter.

[0007] Disadvantages of existing technology:

[0008] The disadvantage of the PFC output voltage control loop is that the bandwidth of the control loop will be relatively narrow if the control is simply based on the PI regulator that controls the output voltage and output current loops. In addition, the dynamic performance of the entire system will be affected because the adjustment speed is not fast enough. Duty cycle feedforward (V0-Vin) / V0 is added on the basis of the average current control method. Setting the duty cycle feedforward control can speed up the response speed of the controller, reduce the control overshoot, and increase the stability of the control system. The adaptive learning control technology using duty cycle feedforward reduces the requirements for the control loop parameters and improves the loop response speed of the PFC output voltage facing various load dynamics.

[0009] If the input voltage is sampled in real time and then the duty cycle feedforward data is obtained through calculation, on the one hand, the CPU computing resources are occupied, and on the other hand, the response speed of the output voltage is slowed down.

[0010] The disadvantages of conventional duty cycle feedforward are:

[0011] By sampling the output voltage and output current in real time, and then calculating (V0-Vin) / V0 through the CPU, and then calculating the output current value, the corresponding PWM signal is finally given to the drive circuit through the CPU. This not only occupies the CPU's computing resources, but also calculates the division inside the CPU, and then sends the corresponding PWM signal to the drive circuit through the CPU. At this time, the output voltage is already lower than the target value.

[0012] In view of this, the present invention is proposed. Summary of the invention

[0013] The purpose of the present invention is to provide an adaptive learning method for PFC circuit duty cycle feedforward control under different load conditions to solve the above technical problems existing in the prior art.

[0014] The objective of the present invention is achieved through the following technical solutions:

[0015] The PFC circuit of the present invention controls the duty cycle feedforward in an adaptive learning method under different load conditions. After the output voltage Vbus is compared with the reference voltage Vref, the output of the voltage loop Vr is obtained after voltage loop calculation, and is sent to the multiplier to be multiplied with the Boost input voltage Vdc to obtain the current reference value iref in the shape of a steamed bun wave;

[0016] After the reference current iref is detected and compared with the switch current is, it passes through the current loop and is then added to the duty cycle feedforward to obtain the duty cycle signal d of the switch tube. After passing through the drive circuit, the switch tube is turned on and off, so that the waveform of the input current (i.e., the inductor current iL) is basically consistent with the waveform of the rectified voltage waveform Vdc;

[0017] When the output voltage is less than the reference voltage Vref, the voltage loop output Vr increases, that is, the reference current value iref increases after passing through the multiplier. Under the action of the current loop, the duty cycle of the switch tube is increased, so that the output voltage is adjusted upward;

[0018] The control strategy used in the above process is:

[0019] Based on the average current control method, duty cycle feedforward (V0-Vin) / V0 control is added, and the duty cycle feedforward adaptive learning control technology is adopted to speed up the response speed of the controller.

[0020] Compared with the prior art, the adaptive learning method of the PFC circuit duty cycle feedforward control under different load conditions provided by the present invention can maintain stable output of the output power supply and provide a stable and reliable power supply for semiconductor equipment, thereby promoting the development of the semiconductor industry and ensuring a stable and reliable semiconductor supply chain, because the duty cycle feedforward (V0-Vin) / V0 control is added on the basis of the average current control method and the adaptive learning control technology of the duty cycle feedforward is adopted. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of the structure and principle of an adaptive learning method for controlling duty cycle feedforward of a PFC circuit under different load conditions provided by an embodiment of the present invention;

[0022] Figure 2 A schematic diagram of connecting a sample power supply of an embodiment of the present invention with an AC source device and an output load device;

[0023] Figure 3 It is a PFC loop control framework of an embodiment of the present invention;

[0024] Figure 4 This is a flow chart of the current loop calculation program according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention; it is obvious that the described embodiments are only part of the embodiments of the present invention, not all of the embodiments, which does not constitute a limitation of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the protection scope of the present invention.

[0026] First, the terms that may be used in this article are explained as follows:

[0027] The term “and / or” means that either or both of them can be realized at the same time. For example, X and / or Y means both “X” or “Y” and “X and Y”.

[0028] The terms "include", "comprises", "contains", "has" or other descriptions with similar semantics should be interpreted as non-exclusive inclusion. For example, including certain technical feature elements (such as raw materials, components, ingredients, carriers, dosage forms, materials, dimensions, parts, components, mechanisms, devices, steps, procedures, methods, reaction conditions, processing conditions, parameters, algorithms, signals, data, products or products, etc.) should be interpreted as including not only certain technical feature elements explicitly listed, but also other technical feature elements known in the art that are not explicitly listed.

[0029] The contents not described in detail in the examples of the present invention belong to the prior art known to professionals in the field. If no specific conditions are specified in the examples of the present invention, the conditions are carried out according to the conventional conditions in the field or the conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used in the examples of the present invention, they are all conventional products that can be purchased commercially.

[0030] The PFC circuit of the present invention controls the duty cycle feedforward in an adaptive learning method under different load conditions. After the output voltage Vbus is compared with the reference voltage Vref, the output of the voltage loop Vr is obtained after voltage loop calculation, and is sent to the multiplier to be multiplied with the Boost input voltage Vdc to obtain the current reference value iref in the shape of a steamed bun wave;

[0031] After the reference current iref is detected and compared with the switch current is, it passes through the current loop and is then added to the duty cycle feedforward to obtain the duty cycle signal d of the switch tube. After passing through the drive circuit, the switch tube is turned on and off, so that the waveform of the input current (i.e., the inductor current iL) is basically consistent with the waveform of the rectified voltage waveform Vdc;

[0032] When the output voltage is less than the reference voltage Vref, the voltage loop output Vr increases, that is, the reference current value iref increases after passing through the multiplier. Under the action of the current loop, the duty cycle of the switch tube is increased, so that the output voltage is adjusted upward;

[0033] The control strategy used in the above process is:

[0034] Based on the average current control method, duty cycle feedforward (V0-Vin) / V0 control is added, and the duty cycle feedforward adaptive learning control technology is adopted to speed up the response speed of the controller.

[0035] The adaptive learning control technology using duty cycle feedforward includes:

[0036] Connect the sample power supply to the input AC source device and the output load device, and control the input target voltage X1 of the input AC source, the output target current Y1 of the output load device, and the output target voltage Z1 through the network port of the host computer. After setting, start the sample power supply, so that the sample power supply obtains a duty cycle feedforward amount λ1 corresponding to the input target voltage, output target current, and output target voltage. Through the input target voltage Xn, the output target current Yn of the output load device, and the output target voltage Zn under different load conditions, the corresponding duty cycle feedforward amount λn is obtained;

[0037] The duty cycle feedforward amount λn is obtained through the above method and a corresponding table is formed and stored in the flah inside the CPU. Then, the sample power supply is shut down and restarted. When the sample power supply samples the input target voltage, output target current, output target voltage and the duty cycle feedforward table, the data is the same, the CPU does not need to calculate (V0-Vin) / V0 anymore, and directly calls the parameters in the duty cycle feedforward table to the drive circuit, which can save CPU calculation time and stabilize the output voltage loop.

[0038] The overall PFC loop control architecture is:

[0039] The loop structure of the outer voltage loop, inner current loop, and duty cycle feedforward compensation. The inner fast circuit loop and feedforward compensation are calculated in the ADC fast interrupt function, and the outer slow voltage loop is calculated in the 1kHz interrupt function.

[0040] The voltage loop output, phase-locked loop phase and input voltage effective value jointly construct the current loop reference quantity. The average current of the sampled inductor is calculated by the PI current loop to obtain the current loop output quantity. The feedforward loop pre-calculates the steady-state initial duty cycle, and the duty cycle is finally controlled by the superimposed current loop calculation.

[0041] The operation of the current inner loop is based on a current reference value, which includes an input voltage phase signal and an output voltage amplitude signal;

[0042] The output of the voltage loop represents the bus voltage being stabilized to the target reference. When the output power is greater, the output of the voltage loop is greater, and when the output power is smaller, the output of the voltage loop is smaller.

[0043] The input voltage phase signal obtained by the phase-locked loop is multiplied by the output of the voltage loop to jointly construct the current reference value; when the input voltage is lower, the input current is greater at the same power; this means that the current reference value also includes the effective value of the input voltage, and the relationship is inversely proportional;

[0044] The current reference value obtained above is:

[0045] Current reference value = voltage loop output * constructed sinusoidal voltage phase signal / input voltage effective value.

[0046] The PFC inner loop uses PI current control, and its reference quantity is the product of the voltage outer loop output and the absolute value of the phase voltage, divided by the square of the effective value of the input voltage, and the feedback quantity is the MOS current;

[0047] In order to suppress the inductor current overcurrent protection caused by excessive reference current at startup, the reference value needs to be multiplied by the soft start coefficient at startup. During the startup process, the current reference value gradually increases;

[0048] Calculate the error between the reference quantity and the inductor current feedback quantity, and obtain the current loop duty cycle output through PI calculation;

[0049] Control duty cycle = feedforward amount + PI current loop output.

[0050] In summary, it can be seen that the adaptive learning method of the PFC circuit control duty cycle feedforward under different load conditions in the embodiment of the present invention first calculates the input voltage and output voltage in the duty cycle feedforward under different load conditions, and then forms an adaptive learning table. Finally, the power supply system directly calls the data in the adaptive learning table under different load conditions, which saves real-time sampling and then the time for calculation, thereby greatly improving the control speed of the power supply output voltage loop and making the output voltage more stable.

[0051] In the present invention, the working principle of PFC is as follows:

[0052] Conventional PFC control includes dual closed-loop control methods, namely output voltage loop and current loop. The voltage loop is used to ensure the stability of the DC bus voltage on the output side, and the current loop is used to ensure that the input inductor current presents a sinusoidal envelope. It is also necessary to add a duty cycle feedforward, so that the output voltage can be stabilized relatively quickly. Figure 1 Shown is a simplified PFC operating principle.

[0053] Duty cycle feedforward concept explanation:

[0054] The duty cycle feedforward is the pre-calculated steady-state control quantity, i.e. (V0-Vin) / V0. Digital control is limited by the CPU main frequency running speed, sampling and loop calculation delay. Usually the current loop design bandwidth is not very high, and the pure loop control effect cannot achieve the inductor current accurately tracking the grid voltage phase.

[0055] To compensate for the insufficient control bandwidth of the current loop, the duty cycle (i.e., the feedforward control quantity) in the steady state is calculated in advance according to the input grid voltage and bus voltage, combined with the DCM and CCM modes in the Boost working mode, and the current loop only performs micro-disturbance control.

[0056] The current loop feedforward is to estimate the duty cycle of the steady-state operating point in advance, and can also be understood as actively providing a steady-state operating point control quantity for the loop control output. This narrows the adjustment range of the current regulator around the steady-state point, making the characteristics of the controlled quantity closer to the ideal waveform.

[0057] In order to more clearly demonstrate the technical solution and technical effects provided by the present invention, the embodiments of the present invention are described in detail with specific examples below.

[0058] Example 1

[0059] like Figure 1 As shown:

[0060] The output voltage Vbus is compared with the reference voltage Vref and then calculated by the voltage loop to obtain the output Vr of the voltage loop, which is sent to the multiplier and multiplied with the Boost input voltage Vdc to obtain the current reference value iref in the shape of a steamed bun wave. The reference current iref is detected and compared with the switch current is, and then passed through the current loop, and then added to the duty cycle feedforward to obtain the duty cycle signal d of the switch tube. After passing through the drive circuit, the switch tube is controlled to be turned on and off, so that the waveform of the input current (i.e., the inductor current iL) is basically consistent with the waveform of the rectified voltage waveform Vdc. When the output voltage is less than the reference voltage Vref, the voltage loop output Vr increases, that is, the reference current value iref increases after passing through the multiplier, and the duty cycle of the switch tube is increased under the action of the current loop, so that the output voltage is adjusted upward.

[0061] Due to the traditional control strategy, which relies solely on the PI regulator that controls the output voltage and output current loop for control and regulation, the bandwidth of the control loop will be relatively narrow.

[0062] The control strategy used in this application adds duty cycle feedforward (V0-Vin) / V0 on the basis of the average current control method. Setting duty cycle feedforward control can speed up the response speed of the controller, but it is necessary to sample the input voltage Vin and the output voltage V0 in real time inside the CPU and then perform calculations, which occupies a large amount of CPU computing resources and reduces the output voltage loop response time.

[0063] like Figure 2 As shown, the adaptive learning control technology of duty cycle feedforward is adopted. After the hardware of the equipment is completed, the sample power supply is connected to the input AC source equipment and the output load equipment. The input target voltage X1 of the input AC source, the output target current Y1 of the output load equipment, and the output target voltage Z1 are respectively controlled through the network port of the host computer. After the settings are completed, the sample power supply is started. In this way, the sample power supply obtains a duty cycle feedforward amount λ1 corresponding to the input target voltage, output target current and output target voltage. The corresponding duty cycle feedforward amount λn is obtained through the input target voltage Xn, the output target current Yn of the output load equipment, and the output target voltage Zn under different load states;

[0064] The duty cycle feedforward amount λn is obtained through the above method and a corresponding table is formed and stored in the flash inside the CPU. Then, the sample power supply is shut down and restarted. When the sample power supply samples the input target voltage, output target current, output target voltage and the duty cycle feedforward table, the data is the same, the CPU does not need to calculate the complex formula (V0-Vin) / V0, and directly calls the parameters in the duty cycle feedforward table to the drive circuit, which greatly saves the CPU calculation time and the output voltage loop is very stable.

[0065] like Figure 3 As shown, it is a loop control framework diagram of an adaptive learning method of a PFC circuit control duty cycle feedforward under different load conditions, where:

[0066] The overall PFC loop control architecture is designed as a loop structure of outer loop voltage, inner loop current, and duty cycle feedforward compensation. The inner loop fast circuit and feedforward compensation are calculated at the ADC fast interrupt function, and the outer loop slow voltage loop is calculated at the 1kHz interrupt function.

[0067] The voltage loop output, phase-locked loop phase, and input voltage effective value jointly construct the current loop reference, sample the average inductor current, and calculate the current loop output through the PI current loop. The feedforward loop pre-calculates the steady-state initial duty cycle, and the duty cycle is calculated by the superimposed current loop to finally control the duty cycle.

[0068] The operation of the current inner loop is based on the current reference value. In order to ensure that the controlled inductor current presents a current waveform with the same envelope as the input voltage, and at the same time ensure that the output voltage is stable at the reference voltage value, the current reference value includes the input voltage phase signal and the output voltage amplitude signal.

[0069] The output of the voltage loop represents the bus voltage stabilizing to the target reference. When the output power is larger, the output of the voltage loop is larger, and when the output power is smaller, the output of the voltage loop is smaller. The input voltage phase signal obtained by the phase-locked loop is multiplied by the output of the voltage loop to jointly construct the current reference value. At the same time, when the input voltage is lower, the input current is larger at the same power, which means that the current reference value also includes the effective value of the input voltage, and the relationship is inversely proportional.

[0070] Based on the above, the current reference value is:

[0071] Current reference value = voltage loop output * constructed sinusoidal voltage phase signal / input voltage effective value

[0072] The PFC inner loop uses PI current control, and its reference is the product of the voltage outer loop output and the absolute value of the phase voltage, divided by the square of the effective value of the input voltage, and the feedback is the MOS current. In order to suppress the inductor current overcurrent protection caused by excessive reference current at startup, the reference needs to be multiplied by the soft start coefficient at startup. During the startup process, the current reference value gradually increases.

[0073] The error between the reference quantity and the inductor current feedback quantity is calculated, and the current loop duty cycle output is obtained through PI calculation.

[0074] Control duty cycle = feedforward amount + PI current loop output.

[0075] The specific current loop design process flow is as follows Figure 4 As shown:

[0076] Adopting the duty cycle feedforward adaptive learning control technology, after the hardware of the equipment is completed, connect the sample power supply to the input AC source equipment and output load equipment, such as Figure 4 As shown, the input target voltage X1 of the input AC source, the output target current Y1 of the output load device, and the output target voltage Z1 are controlled respectively through the network port of the host computer. After setting, the sample power supply is started, so that the sample power supply obtains a duty cycle feedforward amount λ1 corresponding to the input target voltage, output target current, and output target voltage. The corresponding duty cycle feedforward amount λn is obtained through the input target voltage Xn, the output target current Yn of the output load device, and the output target voltage Zn under different load states;

[0077] The duty cycle feedforward amount λn is obtained through the above method and a corresponding table is formed and stored in the flash inside the CPU. Then, the sample power supply is shut down and restarted. When the sample power supply samples the input target voltage, output target current, output target voltage and the duty cycle feedforward table, the data is the same, the CPU does not need to calculate the complex formula (V0-Vin) / V0, and directly calls the parameters in the duty cycle feedforward table to the drive circuit, which greatly saves the CPU calculation time and the output voltage loop is very stable.

[0078] Beneficial effects brought by the technical solution of the invention:

[0079] Through the duty cycle feedforward, adaptive learning is performed under different load conditions, and corresponding tables are formed for the duty cycle feedforward data under different load conditions. In this way, when the output voltage is under the corresponding load condition, the parameters in the data table of the previous adaptive learning are directly called, and finally quickly given to the drive circuit to achieve rapid control of the output voltage loop. Compared with the traditional duty cycle feedforward technology, a PFC circuit in this case controls the duty cycle feedforward under different load conditions. The adaptive learning method saves the CPU real-time sampling and complex calculation time, improves the response time of the output voltage feedback, and ensures that the output voltage is stable and reliable; at the same time, under different load characteristics, it provides a very fast control method for the output voltage loop for capacitive loads (charger loads) and inductive loads (robot loads).

[0080] The present invention performs adaptive learning under different load conditions through duty cycle feedforward, effectively reduces the CPU real-time sampling and complex calculation time, improves the speed of output voltage loop control, and has high practical value and promotion value.

[0081] In the present invention, under different load conditions, the duty cycle feedforward adaptive learning of the PFC circuit forms a duty cycle feedforward mechanism of the power system, making the loop control faster; under different input voltage conditions, the duty cycle feedforward adaptive learning of the PFC circuit forms a duty cycle feedforward mechanism of the power system, making the loop control faster; the output ripple of the PFC circuit is reduced, and the stability of the loop control is improved.

[0082] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed in the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims. The information disclosed in the background technology section of this article is only intended to deepen the understanding of the overall background technology of the present invention, and should not be regarded as an admission or in any form that the information constitutes prior art known to those skilled in the art.

Claims

1. An adaptive learning method for PFC circuit duty cycle feedforward control under different load conditions, characterized in that: After the output voltage Vbus is compared with the reference voltage Vref, the voltage loop output Vr is obtained after voltage loop calculation, which is sent to the multiplier to be multiplied with the Boost input voltage Vdc to obtain the steamed bun wave shaped current reference value iref; After the reference current iref is detected and compared with the switch current is, it passes through the current loop and is then added to the duty cycle feedforward to obtain the duty cycle signal d of the switch tube. After passing through the drive circuit, the switch tube is turned on and off, so that the waveform of the input current (i.e., the inductor current iL) is basically consistent with the waveform of the rectified voltage waveform Vdc; When the output voltage is less than the reference voltage Vref, the voltage loop output Vr increases, that is, the reference current value iref increases after passing through the multiplier. Under the action of the current loop, the duty cycle of the switch tube is increased, so that the output voltage is adjusted upward; The control strategy used in the above process is: Based on the average current control method, duty cycle feedforward (V0-Vin) / V0 control is added, and the duty cycle feedforward adaptive learning control technology is adopted to speed up the response speed of the controller.

2. The adaptive learning method for PFC circuit duty cycle feedforward control under different load conditions according to claim 1, characterized in that: The adaptive learning control technology using duty cycle feedforward includes: Connect the sample power supply to the input AC source device and the output load device, and control the input target voltage X1 of the input AC source, the output target current Y1 of the output load device, and the output target voltage Z1 through the network port of the host computer. After setting, start the sample power supply, so that the sample power supply obtains a duty cycle feedforward amount λ1 corresponding to the input target voltage, output target current, and output target voltage. Through the input target voltage Xn, the output target current Yn of the output load device, and the output target voltage Zn under different load conditions, the corresponding duty cycle feedforward amount λn is obtained; The duty cycle feedforward amount λn is obtained through the above method and a corresponding table is formed and stored in the flah inside the CPU. Then, the sample power supply is shut down and restarted. When the sample power supply samples the input target voltage, output target current, output target voltage and the duty cycle feedforward table, the data is the same, the CPU does not need to calculate (V0-Vin) / V0 anymore, and directly calls the parameters in the duty cycle feedforward table to the drive circuit, which can save CPU calculation time and stabilize the output voltage loop.

3. The adaptive learning method for PFC circuit duty cycle feedforward control under different load conditions according to claim 2, characterized in that: The overall PFC loop control architecture is: The loop structure of the outer voltage loop, inner current loop, and duty cycle feedforward compensation. The inner fast circuit loop and feedforward compensation are calculated in the ADC fast interrupt function, and the outer slow voltage loop is calculated in the 1kHz interrupt function. The voltage loop output, phase-locked loop phase and input voltage effective value jointly construct the current loop reference quantity. The average current of the sampled inductor is calculated by the PI current loop to obtain the current loop output quantity. The feedforward loop pre-calculates the steady-state initial duty cycle, and the duty cycle is finally controlled by the superimposed current loop calculation. The operation of the current inner loop is based on a current reference value, which includes an input voltage phase signal and an output voltage amplitude signal; The output of the voltage loop represents the bus voltage being stabilized to the target reference. When the output power is greater, the output of the voltage loop is greater, and when the output power is smaller, the output of the voltage loop is smaller. The input voltage phase signal obtained by the phase-locked loop is multiplied by the output of the voltage loop to jointly construct the current reference value; when the input voltage is lower, the input current is greater at the same power; this means that the current reference value also includes the effective value of the input voltage, and the relationship is inversely proportional; The current reference value obtained above is: Current reference value = voltage loop output * constructed sinusoidal voltage phase signal / input voltage effective value.

4. The adaptive learning method for PFC circuit duty cycle feedforward control under different load conditions according to claim 3, characterized in that: The PFC inner loop uses PI current control, and its reference quantity is the product of the voltage outer loop output and the absolute value of the phase voltage, divided by the square of the effective value of the input voltage, and the feedback quantity is the MOS current; In order to suppress the inductor current overcurrent protection caused by excessive reference current at startup, the reference value needs to be multiplied by the soft start coefficient at startup. During the startup process, the current reference value gradually increases; Calculate the error between the reference quantity and the inductor current feedback quantity, and obtain the current loop duty cycle output through PI calculation; Control duty cycle = feedforward amount + PI current loop output.

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