A method and system for calibrating air volume for intelligent frequency conversion control of smoke hoods

Abstract

The present invention relates to the field of frequency control technology, and specifically discloses an air volume calibration method and calibration system for intelligent variable frequency control of a smoke hood, wherein the method comprises the following steps: S1: generating coordinate points according to the power frequency and the theoretical speed of the fan, and fitting the coordinate points to obtain a fitting curve; S2: calculating the average power frequency in a sub-period, substituting the average power frequency into the fitting curve to obtain the theoretical speed in the sub-period; calculating the average actual speed according to the actual speed change curve of the fan in the sub-period, and calculating the speed difference; calculating the speed deviation and substituting it into the fitting curve to obtain the first power frequency, and determining the power frequency correction value; S3: determining the correction point according to the power frequency correction value, fitting the correction point to obtain a correction curve, and correcting the power frequency according to the correction curve. The present invention adjusts the air volume by correcting the power frequency to avoid the decrease in the effect of the ventilation system caused by equipment aging.

Description

Technical Field

[0001] The present invention relates to the technical field of frequency control, and in particular to an air volume calibration method and a calibration system for intelligent frequency conversion control of a smoke hood. Background Art

[0002] A hood is a device used on cooking equipment, mainly used to remove fumes, steam and odors generated during the cooking process. The hood is usually installed above the stove and exhausts smoke and air pollutants out of the kitchen through a fan and filtration system, helping to maintain clean air and a healthy indoor environment.

[0003] Hood frequency conversion control refers to the use of frequency conversion technology to adjust and control the fan speed in the kitchen exhaust system to achieve efficient and energy-saving exhaust effects. Specifically, when the fume concentration is high, the inverter increases the frequency, increases the fan speed, increases the air volume, and quickly removes the fume; when the fume concentration is low, the inverter reduces the frequency, reduces the fan speed, and reduces the air volume, thereby saving energy and reducing noise.

[0004] In actual situations, due to the decline in equipment performance caused by aging and other reasons, the motor speed cannot reach the expected value, which in turn leads to a certain gap between the actual air volume and the expected air volume, affecting the overall effect of the ventilation system. Based on this, an air volume calibration method and calibration system for intelligent frequency conversion control of a hood are provided to correct the air volume of the hood and ensure the effect of the ventilation system. Summary of the invention

[0005] The purpose of the present invention is to provide an air volume calibration method and calibration system for intelligent frequency conversion control of a smoke hood to solve the following technical problems:

[0006] The performance of the equipment has declined due to aging and other reasons, so that the motor speed cannot reach the expected value, which in turn causes a certain gap between the actual air volume and the expected air volume, affecting the overall effect of the ventilation system.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] A method for calibrating air volume for intelligent frequency conversion control of a smoke hood comprises the following steps:

[0009] S1: Determine the theoretical speed V of the fan under different power supply frequencies and generate coordinate points (a, V a ), V a Indicates the speed of the fan when the power frequency is a, a∈[U min , U max ],[U min , U max ] is a preset power frequency range, and the coordinate points are fitted to obtain a fitting curve f(x);

[0010] S2: Divide the preset monitoring period [Tsat, Tend] into n sub-periods of the same length, where the sub-period length is T = (Tend-tsta) / n, where n is a preset value, obtain the power frequency in the sub-period in real time and calculate the average power frequency U, and calculate the average power frequency U in the i-th sub-period i Substitute the fitting curve f(x), i∈[1,n], and obtain the theoretical speed VThe in the i-th sub-cycle i ;

[0011] Obtain the actual speed of the fan in the sub-period in real time and draw the actual speed change curve g(t), t∈[0,T], and calculate the average actual speed , calculate the speed difference VDif i =VThe i -Vact i , Vact i represents the average actual speed in the i-th sub-cycle;

[0012] Calculate the speed deviation VDev i =VThe i +VDif i +Vys, Vys represents the preset speed deviation correction value, and the speed deviation VDev i Substitute the fitting curve f(x) to obtain the first power frequency Ufir i , calculate the power frequency correction value Umod i =Ufir i -U i ;

[0013] S3: determining a correction point according to the power supply frequency correction value, fitting the correction point to obtain a correction curve, and correcting the power supply frequency according to the correction curve.

[0014] As a further solution of the present invention: in the step S3, the process of correcting the power frequency according to the correction curve specifically includes:

[0015] Generate correction points (i, Umod i ), fitting the correction points to obtain a correction curve F(x);

[0016] m time nodes are set at equal intervals in [Tend, Tend+T], where m is a preset number. The time corresponding to the time node is substituted into the correction curve F(x) to obtain the power frequency correction value at the time node, and the average power frequency correction value Umod' is calculated. The actual power frequency Ugoa'=Ugoa+Umod' is set, and Ugoa represents the theoretical frequency of the power supply.

[0017] As a further solution of the present invention: when the actual frequency of the power supply Ugoa'>U max When Ugoa'=U max , and send warning information to the background staff.

[0018] As a further solution of the present invention: the process of determining the theoretical frequency Ugoa of the power supply specifically includes:

[0019] The oil fume concentration is collected within [Tend, Tend+T], the target oil fume concentration is set, the power frequency adjustment value for reducing the oil fume concentration to the target oil fume concentration is determined through the PID control algorithm, and the theoretical frequency Ugoa of the power supply is determined according to the power frequency adjustment value.

[0020] As a further solution of the present invention: during the process of collecting the oil fume concentration, when the oil fume concentration is lower than a preset concentration threshold, the fume hood is closed.

[0021] As a further solution of the present invention: in the step S2, the process of calculating the average actual speed also includes the following steps:

[0022] Y evaluation points are set at preset time intervals on the actual speed change curve g(t) to calculate the evaluation difference VPG b '=|VPG b -Vact|,VPG b represents the actual speed corresponding to the bth evaluation point;

[0023] When the evaluation difference VPG b When '≥V'', the actual speed corresponding to the b-th evaluation point is removed, V'' represents the preset evaluation difference threshold, and the average actual speed Vact is calculated again.

[0024] As a further solution of the present invention: in the step S2, during the process of drawing the actual speed change curve g(t), after a sub-cycle ends, the time corresponding to the starting point of the actual speed change curve corresponding to the next adjacent sub-cycle is set to 0.

[0025] An air volume calibration system for intelligent frequency conversion control of a smoke hood, comprising:

[0026] Calibration module: Determine the theoretical speed V of the fan under different power supply frequencies and generate coordinate points (a, V a ), V a Indicates the speed of the fan when the power frequency is a, a∈[U min , U max ],[U min , U max] is a preset power frequency range, and the coordinate points are fitted to obtain a fitting curve f(x);

[0027] Analysis module: Divide the preset monitoring period [Tsat, Tend] into n sub-periods of the same length, where n is a preset value and the sub-period length is T = (Tend-tsta) / n. Obtain the power frequency in the sub-period in real time and calculate the average power frequency U. The average power frequency U in the i-th sub-period is i Substitute the fitting curve f(x), i∈[1,n], and obtain the theoretical speed VThe in the i-th sub-cycle i ;

[0028] Obtain the actual speed of the fan in the sub-period in real time and draw the actual speed change curve g(t), t∈[0,T], and calculate the average actual speed , calculate the speed difference VDif i =VThe i -Vact i , Vact i represents the average actual speed in the i-th sub-cycle;

[0029] Calculate the speed deviation VDev i =VThe i +VDif i +Vys, Vys represents the preset speed deviation correction value, and the speed deviation VDev i Substitute the fitting curve f(x) to obtain the first power frequency Ufir i , calculate the power frequency correction value Umod i =Ufir i -U i ;

[0030] Correction module: determine correction points according to the power supply frequency correction value, fit the correction points to obtain a correction curve, and correct the power supply frequency according to the correction curve.

[0031] Beneficial effects of the present invention: In the present invention, the theoretical speed of the fan under different power supply frequencies is first determined, and coordinate points are generated to determine the fitting curve; it can be understood that the theoretical speed is the fan speed that is not affected by aging and other reasons, which is the basis for the subsequent calibration of the air volume, and setting the power supply frequency range is to ensure that the power supply frequency will not exceed the upper limit and cause a safety accident, and limiting the power supply frequency range can reduce the amount of data that needs to be processed later, saving computing resources; then the sub-period is divided, and the average power supply frequency determined in each sub-period is substituted into the fitting curve to obtain the theoretical speed in the sub-period; it can be understood that dividing the sub-period and determining the average power supply frequency in the sub-period can reduce the amount of data that needs to be processed later, and the average power supply frequency reflects the average situation of the power supply frequency in the sub-period. In the subsequent steps, the theoretical speed and the actual speed of the same sub-period can be compared as a whole, thereby reducing the complexity of the subsequent determination of the speed difference; then the speed difference is determined according to the difference between the theoretical speed and the actual speed, the speed deviation is calculated, and the power supply frequency correction value is determined based on this; it should be noted that, The speed difference reflects the deviation between the theoretical speed and the actual speed, and determines the speed deviation, so as to determine the power frequency correction value required for the actual speed to reach the theoretical speed, that is, how much the power frequency needs to be increased so that the actual speed in the sub-period can reach the theoretical speed; finally, the correction point is determined according to the power frequency correction value, the correction point is fitted to obtain a correction curve, and the power frequency is corrected according to the correction curve; it is worth noting that the reasons for not directly using the first power frequency to perform the subsequent process, but performing the subsequent process by calculating the power frequency correction value include: in the subsequent use of the hood, due to various reasons such as a sudden increase in the fume concentration, the actual required power frequency may increase accordingly. In this case, the curve fitted by the first power frequency predicts the required power frequency and there will be obvious deviations. Therefore, in this scheme, by introducing the power frequency correction value parameter, the predicted power frequency correction value is added to the power frequency corresponding to the detected fume concentration (that is, the theoretical frequency Ugoa), which can reduce the error in the above situation. The present invention adjusts the air volume by correcting the power frequency to avoid the decline in the effect of the ventilation system caused by equipment aging. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention will be further described below in conjunction with the accompanying drawings.

[0033] Figure 1 The invention discloses a flow chart of an air volume calibration method and a calibration system for intelligent frequency conversion control of a smoke hood. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] See also Figure 1 As shown, the present invention is a method for calibrating air volume for intelligent frequency conversion control of a smoke hood, comprising the following steps:

[0036] S1: Determine the theoretical speed V of the fan under different power supply frequencies and generate coordinate points (a, V a ), V a Indicates the speed of the fan when the power frequency is a, a∈[U min , U max ],[U min , U max ] is a preset power frequency range, and the coordinate points are fitted to obtain a fitting curve f(x);

[0037] S2: Divide the preset monitoring period [Tsat, Tend] into n sub-periods of the same length, where the sub-period length is T = (Tend-tsta) / n, where n is a preset value, obtain the power frequency in the sub-period in real time and calculate the average power frequency U, and calculate the average power frequency U in the i-th sub-period i Substitute the fitting curve f(x), i∈[1,n], and obtain the theoretical speed VThe in the i-th sub-cycle i ;

[0038] Obtain the actual speed of the fan in the sub-period in real time and draw the actual speed change curve g(t), t∈[0,T], and calculate the average actual speed , calculate the speed difference VDif i =VThe i -Vact i , Vact i represents the average actual speed in the i-th sub-cycle;

[0039] Calculate the speed deviation VDev i =VThe i +VDif i +Vys, Vys represents the preset speed deviation correction value, and the speed deviation VDev i Substitute the fitting curve f(x) to obtain the first power frequency Ufir i , calculate the power frequency correction value Umod i =Ufir i-U i ;

[0040] S3: determining a correction point according to the power supply frequency correction value, fitting the correction point to obtain a correction curve, and correcting the power supply frequency according to the correction curve.

[0041] It should be noted that the theoretical speed of the fan under different power supply frequencies is first determined, and coordinate points are generated to determine the fitting curve; it can be understood that the theoretical speed is the fan speed that is not affected by aging and other reasons, which is the basis for the subsequent calibration of the air volume, and setting the power supply frequency range is to ensure that the power supply frequency will not exceed the upper limit and cause a safety accident, and limiting the power supply frequency range can reduce the amount of data that needs to be processed later and save computing resources; then the sub-period is divided, and the average power supply frequency determined in each sub-period is substituted into the fitting curve to obtain the theoretical speed in the sub-period; it can be understood that dividing the sub-period and determining the average power supply frequency in the sub-period can reduce the amount of data that needs to be processed later, and the average power supply frequency reflects the average situation of the power supply frequency in the sub-period. In the subsequent steps, the theoretical speed and the actual speed of the same sub-period can be compared as a whole, thereby reducing the complexity of the subsequent determination of the speed difference; then the speed difference is determined according to the difference between the theoretical speed and the actual speed, the speed deviation is calculated, and the power supply frequency correction value is determined based on this; it should be noted that the speed difference It reflects the deviation between the theoretical speed and the actual speed, and determines the speed deviation, so as to determine the power frequency correction value required for the actual speed to reach the theoretical speed, that is, how much the power frequency needs to be increased to make the actual speed in the sub-period reach the theoretical speed; finally, the correction point is determined according to the power frequency correction value, the correction point is fitted to obtain a correction curve, and the power frequency is corrected according to the correction curve; it is worth noting that the reasons for not directly using the first power frequency to execute the subsequent process but executing the subsequent process by calculating the power frequency correction value include: in the subsequent use of the fume hood, various reasons such as a sudden increase in the fume concentration may cause the actual required power frequency to increase accordingly. In this case, the required power frequency predicted by the curve fitted by the first power frequency will have obvious deviations. Therefore, in this scheme, by introducing the power frequency correction value parameter, the predicted power frequency correction value is added to the power frequency corresponding to the detected fume concentration (that is, the theoretical frequency Ugoa), which can reduce the error in the above situation.

[0042] In another preferred embodiment of the present invention, in step S3, the process of correcting the power frequency according to the correction curve specifically includes:

[0043] Generate correction points (i, Umod i ), fitting the correction points to obtain a correction curve F(x);

[0044] m time nodes are set at equal intervals in [Tend, Tend+T], where m is a preset number. The time corresponding to the time node is substituted into the correction curve F(x) to obtain the power frequency correction value at the time node, and the average power frequency correction value Umod' is calculated. The actual power frequency Ugoa'=Ugoa+Umod' is set, and Ugoa represents the theoretical frequency of the power supply.

[0045] It is worth noting that by sampling the correction values ​​at multiple nodes in the subsequent time period, the frequency change trend of the correction curve during this period can be captured. This method can eliminate accidental errors and provide a more stable correction result; by averaging the frequency correction values ​​at multiple time nodes, the fluctuation of the correction value is further smoothed, reducing the impact of abnormal conditions at a single moment (such as sudden fluctuations) on the overall correction result.

[0046] In another preferred embodiment of the present invention, when the actual power frequency Ugoa'>U max When Ugoa'=U max , and send warning information to the background staff.

[0047] In another preferred embodiment of the present invention, the process of determining the theoretical frequency Ugoa of the power supply specifically includes:

[0048] The oil fume concentration is collected within [Tend, Tend+T], the target oil fume concentration is set, the power frequency adjustment value for reducing the oil fume concentration to the target oil fume concentration is determined through the PID control algorithm, and the theoretical frequency Ugoa of the power supply is determined according to the power frequency adjustment value.

[0049] It should be noted that the target oil fume concentration value is the benchmark of the control process. All control operations are aimed at reducing the current oil fume concentration to this target value. This target is set to ensure that the system operates within the range of environmental protection or other standards while achieving the expected operating results. The PID control algorithm is a common feedback control algorithm. By adjusting the proportional, integral and differential parts, the output of the system can be effectively controlled. In this solution, PID control is used to determine the size of the power supply frequency adjustment to reduce the gap between the oil fume concentration and the target value, ensuring that the oil fume concentration can be reduced to the target level as expected.

[0050] In another preferred embodiment of the present invention, during the process of collecting the oil fume concentration, when the oil fume concentration is lower than a preset concentration threshold, the fume hood is closed.

[0051] In another preferred embodiment of the present invention, in step S2, the process of calculating the average actual speed further includes the following steps:

[0052] Y evaluation points are set at preset time intervals on the actual speed change curve g(t) to calculate the evaluation difference VPG b '=|VPG b -Vact|,VPG b represents the actual speed corresponding to the bth evaluation point;

[0053] When the evaluation difference VPG b When '≥V'', the actual speed corresponding to the b-th evaluation point is removed, V'' represents the preset evaluation difference threshold, and the average actual speed Vact is calculated again.

[0054] It is understandable that by setting multiple evaluation points on the actual speed change curve and calculating the difference between the actual speed of each evaluation point and the overall actual speed, those abnormal points that do not conform to the overall trend can be identified. If the evaluation difference exceeds the preset evaluation difference threshold, it is considered that the actual speed of the point may be affected by instantaneous interference or error, and will be excluded from the average calculation, which helps to eliminate abnormal data points caused by sudden fluctuations, sensor errors or other external factors, thereby ensuring that the final calculated average actual speed is more accurate and stable.

[0055] In another preferred embodiment of the present invention, in the step S2, during the process of drawing the actual speed change curve g(t), after a sub-cycle ends, the time corresponding to the starting point of the actual speed change curve corresponding to the next adjacent sub-cycle is set to 0.

[0056] It is worth noting that

[0057] An air volume calibration system for intelligent frequency conversion control of a smoke hood, comprising:

[0058] Calibration module: Determine the theoretical speed V of the fan under different power supply frequencies and generate coordinate points (a, V a ), V a Indicates the speed of the fan when the power frequency is a, a∈[U min , U max ],[U min , U max ] is a preset power frequency range, and the coordinate points are fitted to obtain a fitting curve f(x);

[0059] Analysis module: Divide the preset monitoring period [Tsat, Tend] into n sub-periods of the same length, where n is a preset value and the sub-period length is T = (Tend-tsta) / n. Obtain the power frequency in the sub-period in real time and calculate the average power frequency U. The average power frequency U in the i-th sub-period is iSubstitute the fitting curve f(x), i∈[1,n], and obtain the theoretical speed VThe in the i-th sub-cycle i ;

[0060] Obtain the actual speed of the fan in the sub-period in real time and draw the actual speed change curve g(t), t∈[0,T], and calculate the average actual speed , calculate the speed difference VDif i =VThe i -Vact i , Vact i represents the average actual speed in the i-th sub-cycle;

[0061] Calculate the speed deviation VDev i =VThe i +VDif i +Vys, Vys represents the preset speed deviation correction value, and the speed deviation VDev i Substitute the fitting curve f(x) to obtain the first power frequency Ufir i , calculate the power frequency correction value Umod i =Ufir i -U i ;

[0062] Correction module: determine correction points according to the power supply frequency correction value, fit the correction points to obtain a correction curve, and correct the power supply frequency according to the correction curve.

[0063] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A method for calibrating air volume for intelligent frequency conversion control of a smoke hood, characterized in that: The following steps are involved: S1: Determine the theoretical speed V of the fan under different power supply frequencies and generate coordinate points (a, V a ), V a represents the speed of the fan when the power frequency is a, a∈[U min , U max ],[U min , U max ] is a preset power frequency range, and the coordinate points are fitted to obtain a fitting curve f(x); S2: Divide the preset monitoring period [Tsat, Tend] into n sub-periods of the same length, where the sub-period length is T = (Tend-tsta) / n, where n is a preset value, obtain the power frequency in the sub-period in real time and calculate the average power frequency U, and calculate the average power frequency U in the i-th sub-period i Substitute the fitting curve f(x), i∈[1,n], and obtain the theoretical speed VThe in the i-th sub-cycle i ; Obtain the actual speed of the fan in the sub-period in real time and draw the actual speed change curve g(t), t∈[0,T], and calculate the average actual speed , calculate the speed difference VDif i =VThe i -Vact i , Vact i represents the average actual speed in the i-th sub-cycle; Calculate the speed deviation VDev i =VThe i +VDif i +Vys, Vys represents the preset speed deviation correction value, and the speed deviation VDev i Substitute the fitting curve f(x) to obtain the first power frequency Ufir i , calculate the power frequency correction value Umod i =Ufir i -U i ; S3: determining a correction point according to the power frequency correction value, fitting the correction point to obtain a correction curve, and correcting the power frequency according to the correction curve; The process of correcting the power frequency according to the correction curve specifically includes: Generate correction points (i, Umod i ), fitting the correction points to obtain a correction curve F(x); m time nodes are set at equal intervals in [Tend, Tend+T], where m is a preset number. The time corresponding to the time node is substituted into the correction curve F(x) to obtain the power frequency correction value at the time node, and the average power frequency correction value Umod' is calculated. The actual power frequency Ugoa'=Ugoa+Umod' is set, and Ugoa represents the theoretical frequency of the power supply.

2. The air volume calibration method for intelligent frequency conversion control of a smoke hood according to claim 1 is characterized in that: When the actual frequency of the power supply Ugoa'>U max When Ugoa'=U max , and send warning information to the background staff.

3. The air volume calibration method for intelligent frequency conversion control of a smoke hood according to claim 1 is characterized in that: The process of determining the theoretical frequency Ugoa of the power supply specifically includes: The oil fume concentration is collected within [Tend, Tend+T], the target oil fume concentration is set, the power frequency adjustment value for reducing the oil fume concentration to the target oil fume concentration is determined through the PID control algorithm, and the theoretical frequency Ugoa of the power supply is determined according to the power frequency adjustment value.

4. The air volume calibration method for intelligent frequency conversion control of a smoke hood according to claim 3 is characterized in that: During the process of collecting the oil fume concentration, when the oil fume concentration is lower than the preset concentration threshold, the fume hood is closed.

5. The air volume calibration method for intelligent frequency conversion control of a smoke hood according to claim 1, characterized in that: In the step S2, the process of calculating the average actual speed also includes the following steps: Y evaluation points are set at preset time intervals on the actual speed change curve g(t) to calculate the evaluation difference VPG b '=|VPG b -Vact|,VPG b represents the actual speed corresponding to the bth evaluation point; When the evaluation difference VPG b When '≥V'', the actual speed corresponding to the b-th evaluation point is removed, V'' represents the preset evaluation difference threshold, and the average actual speed Vact is calculated again.

6. The air volume calibration method for intelligent frequency conversion control of a smoke hood according to claim 1, characterized in that: In the step S2, during the process of drawing the actual speed change curve g(t), after a sub-cycle ends, the time corresponding to the starting point of the actual speed change curve corresponding to the next adjacent sub-cycle is set to 0.

7. An air volume calibration system for intelligent frequency conversion control of a smoke hood, characterized in that: include: Calibration module: Determine the theoretical speed V of the fan under different power supply frequencies and generate coordinate points (a, V a ), V a represents the speed of the fan when the power frequency is a, a∈[U min , U max ],[U min , U max ] is a preset power frequency range, and the coordinate points are fitted to obtain a fitting curve f(x); Analysis module: Divide the preset monitoring period [Tsat, Tend] into n sub-periods of the same length, where n is a preset value and the sub-period length is T = (Tend-tsta) / n. Obtain the power frequency in the sub-period in real time and calculate the average power frequency U. The average power frequency U in the i-th sub-period is i Substitute the fitting curve f(x), i∈[1,n], and obtain the theoretical speed VThe in the i-th sub-cycle i ; Obtain the actual speed of the fan in the sub-period in real time and draw the actual speed change curve g(t), t∈[0,T], and calculate the average actual speed , calculate the speed difference VDif i =VThe i -Vact i , Vact i represents the average actual speed in the i-th sub-cycle; Calculate the speed deviation VDev i =VThe i +VDif i +Vys, Vys represents the preset speed deviation correction value, and the speed deviation VDev i Substitute the fitting curve f(x) to obtain the first power frequency Ufir i , calculate the power frequency correction value Umod i =Ufir i -U i ; Correction module: determining a correction point according to the power frequency correction value, fitting the correction point to obtain a correction curve, and correcting the power frequency according to the correction curve; The process of correcting the power frequency according to the correction curve specifically includes: Generate correction points (i, Umod i ), fitting the correction points to obtain a correction curve F(x); m time nodes are set at equal intervals in [Tend, Tend+T], where m is a preset number. The time corresponding to the time node is substituted into the correction curve F(x) to obtain the power frequency correction value at the time node, and the average power frequency correction value Umod' is calculated. The actual power frequency Ugoa'=Ugoa+Umod' is set, and Ugoa represents the theoretical frequency of the power supply.

Images