Load self-adaption control method and system during closed-loop starting of variable frequency controller

Abstract

The invention discloses a load self-adaption control method and system during closed-loop starting of a variable-frequency controller, and relates to the technical field of variable-frequency control. The load self-adaption control method during closed-loop starting of the variable-frequency controller comprises the following steps: acquiring a width pulse modulation signal; acquiring a level proportion degree; acquiring a feedback signal; and closed-loop feedback. According to the invention, the output load value of the duty ratio variable frequency controller is obtained and converted into the corresponding pulse width modulation signal, and the level ratio degree is obtained according to the output duty ratio of the pulse width modulation signal and is input into the duty ratio variable frequency controller to obtain the feedback signal; and then the feedback signal is converted into the feedback value to obtain the error rate and perform closed-loop feedback, so that the effect of improving the output duty ratio adjustment efficiency of the duty ratio variable frequency controller in the preset time period is achieved, and the problem of low output duty ratio adjustment efficiency of the duty ratio variable frequency controller in the preset time period in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of variable frequency control, and in particular to a load adaptive control method and system during closed-loop startup of a variable frequency controller. Background Art

[0002] With the continuous development of industrial automation and intelligent control technology, frequency conversion controllers are increasingly used in various motor drive systems, and their intelligence level directly affects the performance of the entire system. Secondly, with the continuous advancement of sensor technology, microprocessor technology and control algorithms, closed-loop control technology has been widely used in many fields and has shown its unique advantages. Applying it to the field of frequency conversion control can significantly improve the control accuracy and stability of the system. Traditional starting methods often use a fixed frequency increase rate for closed-loop starting. This method can achieve good results when the load is relatively stable, but when the load changes greatly, it is easy to cause problems such as starting failure or motor loss of step. Therefore, how to enable the frequency conversion controller to adaptively adjust the frequency increase rate during closed-loop starting to adapt to different load conditions has become a technical problem that needs to be solved urgently.

[0003] The existing variable frequency controller detects the actual load of the variable frequency air conditioner in real time through built-in sensors and detection equipment, maps the actual load change with the preset frequency increase rate according to the change in the preset time period, and sets a preheating mechanism and a protection mechanism to prevent the controller from being damaged due to excessive load during the startup of the variable frequency air conditioner, thereby realizing the startup of the variable frequency controller at the optimal frequency increase rate. However, in the prior art, the actual load change of the variable frequency controller within the preset time period has a low match with the preset load, resulting in the preset frequency increase rate being unable to adapt to all load changes within the preset time period, and there is a problem of low efficiency in adjusting the output duty cycle of the duty cycle variable frequency controller within the preset time period. Summary of the invention

[0004] The embodiment of the present invention solves the problem of low output duty cycle adjustment efficiency of the duty cycle variable frequency controller within a preset time period in the prior art by providing a control method and system for load adaptation during closed-loop startup of the variable frequency controller, thereby achieving improvement in the output duty cycle adjustment efficiency of the duty cycle variable frequency controller within the preset time period.

[0005] An embodiment of the present invention provides a method for controlling load adaptation during closed-loop startup of a variable frequency controller, comprising the following steps:

[0006] S1, obtaining an output load value of the duty cycle frequency conversion controller within a preset time period, and converting the output load value into a corresponding pulse width modulation signal, wherein the output load value is used to reflect the load change of the duty cycle frequency conversion controller within the preset time period, and the pulse width modulation signal includes a high level signal, a low level signal and an equal level signal;

[0007] S2, mapping the output load value within the preset time period to the output duty cycle of the pulse width modulation signal to obtain a level proportion, wherein the output duty cycle includes a high level duty cycle and a low level duty cycle, and the level proportion is used to measure the proportion of the high level duty cycle and the low level duty cycle in the output duty cycle within the preset period;

[0008] S3, real-time monitoring of the change of the output duty cycle of the pulse width modulation signal, and inputting the acquired level proportion into the PID control algorithm set in the duty cycle frequency conversion controller to obtain a feedback signal, wherein the feedback signal is the output duty cycle change amount that needs to be adjusted by the PID control algorithm;

[0009] S4, converts the feedback signal into a feedback value and compares it with the target value to obtain the error rate, and performs closed-loop feedback and determines whether the output duty cycle of the closed-loop feedback meets the preset duty cycle error threshold. If so, the current operating status and output duty cycle of the duty cycle frequency converter are recorded and fed back to the preset management personnel. The error rate is used to measure the degree of deviation between the feedback value and the target value.

[0010] Optionally, the step of converting the output load value into a corresponding pulse width modulation signal further includes obtaining a duty cycle amplitude coefficient according to the pulse width modulation signal; the duty cycle amplitude coefficient is the sum of a high level amplitude coefficient and a low level amplitude coefficient, the high level amplitude coefficient is used to measure the continuous proportion of the high level signal within a preset period, and the low level amplitude coefficient is used to measure the continuous proportion of the low level signal within a preset period; the duty cycle amplitude coefficient is calculated by the following formula:

[0011] ;

[0012] ;

[0013] ;

[0014] Where y is the number of the preset cycle, , Q is the total number of preset cycles, g is the number of high-level signals, , G is the total number of high-level signals, d is the number of low-level signals, , D is the total number of low-level signals, e is a natural constant, represents the duty cycle amplitude coefficient of the pulse width modulation signal in the yth preset period, represents the high level amplitude coefficient of the high level signal in the pulse width modulation signal in the yth preset period, represents the low-level amplitude coefficient of the low-level signal in the pulse width modulation signal in the y-th preset period, represents the high-level signal duration of the g-th high-level signal in the pulse width modulation signal within the y-th preset period, Indicates the reference duration of the high level signal. Indicates the high level signal duration correction factor, represents the low-level signal duration of the d-th low-level signal in the pulse width modulation signal within the y-th preset cycle, Indicates the reference duration of the low level signal. Indicates the low-level signal duration correction factor.

[0015] Optionally, the specific steps of mapping the output load value within the preset time period to the output duty cycle of the pulse width modulation signal include: acquiring in real time the time period in which the output load value increases within the preset cycle and acquiring the high-level duty cycle in combination with the duration of the high-level signal, and acquiring in real time the time period in which the output load value decreases within the preset cycle and acquiring the low-level duty cycle in combination with the duration of the low-level signal, the high-level duty cycle representing the ratio of the duration of the high-level signal to the preset time period, and the low-level duty cycle representing the ratio of the duration of the low-level signal to the preset time period; generating a corresponding pulse width modulation signal according to the acquired high-level duty cycle and low-level duty cycle, and monitoring in real time the frequency change trend of the pulse width modulation signal within the preset cycle according to the amplitude signals of the high-level signal and the low-level signal, the amplitude signal being used to reflect the peak values ​​of the high-level signal and the low-level signal within the preset cycle.

[0016] Optionally, the step of obtaining the level proportion degree also includes real-time monitoring of changes in the high-level duty cycle and the low-level duty cycle in the pulse width modulation signal within a preset period. When the high-level duty cycle is not greater than the low-level duty cycle, the output load value of the duty cycle frequency conversion controller within a preset time period is obtained. Otherwise, the level proportion degree is calculated by the following formula:

[0017] ;

[0018] Where y is the number of the preset cycle, , Q is the total number of preset cycles, g is the number of high-level signals, , G is the total number of high-level signals, d is the number of low-level signals, , D is the total number of low-level signals, e is a natural constant, Indicates the level proportion of the pulse width modulation signal in the yth preset cycle, represents the high level duty cycle of the g-th high level signal in the pulse width modulation signal in the y-th preset period, Indicates the high level reference duty cycle, represents the low-level duty cycle of the d-th low-level signal in the pulse width modulation signal within the y-th preset period, Indicates the low level reference duty cycle.

[0019] Optionally, the feedback signal is converted into a feedback value and compared with a target value to obtain an error rate, and then the control items corresponding to the control parameters of the PID control algorithm are added and combined with the obtained error rate to obtain a total output of the PID control algorithm, wherein the control items include a proportional item, an integral item and a differential item. The total output of the PID control algorithm is used to reflect the control of the output error rate by the PID control algorithm within a preset time period. The specific calculation formula of the total output of the PID control algorithm is:

[0020] ;

[0021] Where t is the number of the preset time period, , T is the total number of preset time periods, is the tth preset time period, ,in is any point in the tth preset time period, y is the number of the preset period, , Q is the total number of preset cycles, represents the total output of the PID control algorithm in the tth preset time period, represents the error rate of the feedback signal in the t-th preset time period in the y-th preset period, represents the proportionality constant, represents the integration constant, represents the differential constant.

[0022] The embodiment of the present invention provides a control system for load self-adaptation during closed-loop startup of a frequency conversion controller, comprising: a pulse width modulation signal acquisition module, a level proportion degree acquisition module, a feedback signal acquisition module and a closed-loop feedback module; wherein the pulse width modulation signal acquisition module is used to acquire the output load value of the duty cycle frequency conversion controller within a preset time period, and at the same time convert the output load value into a corresponding pulse width modulation signal, the output load value is used to reflect the load change of the duty cycle frequency conversion controller within the preset time period, the pulse width modulation signal includes a high level signal, a low level signal and an equal level signal; the level proportion degree acquisition module is used to map the output load value within the preset time period to the output duty cycle of the pulse width modulation signal to obtain the level proportion degree, the output duty cycle includes a high level duty cycle and a low level duty cycle, and the level proportion degree is used to measure the high level duty cycle and the low level duty cycle within a preset period. The feedback signal acquisition module is used to monitor the change of the output duty cycle of the pulse width modulation signal in real time, and at the same time input the acquired level proportion into the PID control algorithm set in the duty cycle frequency conversion controller to obtain a feedback signal, and the feedback signal is the output duty cycle change amount that the PID control algorithm needs to adjust; the closed-loop control module is used to convert the feedback signal into a feedback value and compare it with the target value to obtain an error rate, and at the same time perform closed-loop feedback and determine whether the output duty cycle of the closed-loop feedback meets the preset duty cycle error threshold. If so, the current operating status and output duty cycle of the duty cycle frequency conversion controller are recorded and fed back to the preset management personnel, otherwise the closed-loop feedback is performed again until the output duty cycle of the closed-loop feedback meets the preset duty cycle error threshold. The target value is the duty cycle corresponding to the preset output power, and the error rate is used to measure the degree of deviation between the feedback value and the target value.

[0023] Compared with the prior art, the above technical solution has at least the following beneficial effects:

[0024] The above scheme is a control method for load adaptation during closed-loop startup of a frequency conversion controller, which obtains the output load value of the duty cycle frequency conversion controller and converts it into a corresponding pulse width modulation signal, then obtains the level proportion degree by the output duty cycle of the pulse width modulation signal and inputs it into the duty cycle frequency conversion controller to obtain a feedback signal, and finally converts the feedback signal into a feedback value to obtain an error rate and performs closed-loop feedback, thereby achieving more accurate acquisition of the level proportion degree, and further achieving an improvement in the output duty cycle adjustment efficiency of the duty cycle frequency conversion controller within a preset time period, effectively solving the problem of low output duty cycle adjustment efficiency of the duty cycle frequency conversion controller within a preset time period in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 A flow chart of a method for controlling load adaptation during closed-loop startup of a variable frequency controller provided by an embodiment of the present invention;

[0027] Figure 2 A three-dimensional coordinate analysis diagram of the error rate provided by an embodiment of the present invention;

[0028] Figure 3 A schematic structural diagram of a load adaptive control system during closed-loop startup of a variable frequency controller provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment 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.

[0030] Unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one", "one" or "the" do not indicate a quantitative limitation, but indicate the existence of at least one. Words such as "include" or "comprise" mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0031] It should be noted that the terms "up", "down", "left", "right", "front", "back", etc. used in the present invention are only used to indicate relative position relationships. When the absolute position of the object being described changes, the relative position relationship may also change accordingly.

[0032] The present invention aims to solve the problem that the actual load change of the existing frequency conversion controller within a preset time period has a low match with the preset load, and the preset frequency increase rate cannot adapt to all load changes within the preset time period, thereby reducing the low efficiency of adjusting the output duty cycle of the duty cycle frequency conversion controller within the preset time period. A control method for load adaptation during closed-loop startup of the frequency conversion controller is provided, and the adjustment efficiency of the output duty cycle of the duty cycle frequency conversion controller within the preset time period is effectively improved.

[0033] like Figure 1 As shown, it is a flow chart of a control method for load adaptation during closed-loop startup of a variable frequency controller provided by an embodiment of the present invention, and the method comprises the following steps:

[0034] S1, obtain the output load value of the duty cycle frequency conversion controller within a preset time period, and convert the output load value into a corresponding pulse width modulation signal. The output load value is used to reflect the load change of the duty cycle frequency conversion controller within the preset time period. The pulse width modulation signal includes a high-level signal, a low-level signal and an equal-level signal. The high-level signal is used to reflect the process of the output load value increasing within a preset period, the low-level signal is used to reflect the process of the output load value decreasing within the preset period, and the equal-level signal is used to reflect the process of the output load value remaining unchanged within the preset period. The high-level signal is greater than the low-level signal.

[0035] S2, mapping the output load value within the preset time period to the output duty cycle of the pulse width modulation signal to obtain the level proportion degree, the output duty cycle includes a high level duty cycle and a low level duty cycle, the high level duty cycle is used to reflect the increase degree of the output load value within the preset period, the low level duty cycle is used to reflect the decrease degree of the output load value within the preset period, and the level proportion degree is used to measure the proportion of the high level duty cycle and the low level duty cycle in the output duty cycle within the preset period.

[0036] S3, real-time monitoring of the change of the output duty cycle of the pulse width modulation signal, and inputting the acquired level proportion into the PID control algorithm set in the duty cycle frequency conversion controller to obtain a feedback signal, and the feedback signal is the output duty cycle change amount that the PID control algorithm needs to adjust.

[0037] S4, converts the feedback signal into a feedback value and compares it with the target value to obtain the error rate, and performs closed-loop feedback at the same time to determine whether the output duty cycle of the closed-loop feedback meets the preset duty cycle error threshold. If so, the current operating status and output duty cycle of the duty cycle frequency converter are recorded and fed back to the preset management personnel, otherwise the closed-loop feedback is performed again until the output duty cycle of the closed-loop feedback meets the preset duty cycle error threshold. The target value is the duty cycle corresponding to the preset output power. The error rate is used to measure the degree of deviation between the feedback value and the target value. The closed-loop feedback is used to adjust the output duty cycle of the pulse width modulation signal in real time according to the control parameters of the PID control algorithm. The duty cycle error threshold represents the difference between the maximum allowable error and the minimum allowable error of the closed-loop feedback output duty cycle.

[0038] In this embodiment, in a pulse width modulation (PWM) signal, the duty cycle refers to the proportion of time occupied by a high level (or called an "on" state) in a complete cycle. For example, if the cycle is 1 second and the high level lasts for 0.5 seconds, the duty cycle is 50%. The PWM signal is a method of digitally encoding analog signal levels, and different analog signal levels are simulated by high-resolution duty cycle changes. In practical applications, it is necessary to clearly define the possible range of output load values ​​(for example, a percentage from 0 to 100, or from 0 to a certain maximum current / voltage value) and the range of the PWM signal duty cycle (usually 0% to 100%). Then, based on the range of the load value and the duty cycle, a simple linear equation can be used to represent the relationship between them. For example, if the load value range is 0 to 100 and the duty cycle range is also 0% to 100%, the mapping function is usually that the duty cycle is equal to the load value divided by 100 (note that in actual implementation, the duty cycle may need to be converted into a format accepted by the PWM controller, such as an integer from 0 to 255).

[0039] Specifically, the preset period is usually a fixed time interval used to measure and adjust the change of the output load value. Within the preset period, when the output load value increases, the proportion of the time occupied by the high level in the PWM signal; within the preset period, when the output load value decreases, the proportion of the time occupied by the low level in the PWM signal; according to the changing trend of the output load value (increase or decrease), the corresponding high level or low level duty cycle is obtained, wherein the high level proportion is usually the ratio of the time occupied by the high level in the PWM signal to the preset period, and the low level proportion is usually the ratio of the time occupied by the low level in the PWM signal to the preset period. For example, if within a preset period, the high level duty cycle is 60% and the low level duty cycle is 20%, then the level proportion can be simply expressed as 60% high level and 20% low level, thereby improving the output duty cycle adjustment efficiency of the duty cycle variable frequency controller within the preset time period.

[0040] Optionally, the output load value of the duty cycle frequency conversion controller within a preset time period is obtained, and the preheating treatment is also included before starting the duty cycle frequency conversion controller. The preheating treatment is used to reduce the starting load of the duty cycle frequency conversion controller in a preset low temperature environment. The specific process of the preheating treatment is: measure the actual temperature of the duty cycle frequency conversion controller before starting in the preset low temperature environment through a temperature sensor and compare it with the preset starting temperature to obtain the temperature difference. The preset starting temperature is set according to the actual preheating requirement of the duty cycle frequency conversion controller. The temperature difference represents the difference between the actual temperature before the duty cycle frequency conversion controller starts and the preset starting temperature; set the corresponding preheating value according to the obtained temperature difference and start the duty cycle frequency conversion controller within the unit preheating time until the temperature generated by the heating element in the duty cycle frequency conversion controller is equal to the preset starting temperature. The preheating value is the preheating temperature of the duty cycle frequency conversion controller. The heating element includes a resistance wire, an electric heating tube and a heating film.

[0041] In this embodiment, the preset startup temperature should be higher than the lowest ambient temperature at which the controller can start safely, and is usually represented by the result of summing and averaging the ambient temperature data in the preset database; the measured actual temperature is compared with the set preset startup temperature, and the difference between the two, that is, the temperature difference (the difference between the actual temperature and the preset startup temperature), is calculated. This difference will be used to determine whether preheating treatment is required and the intensity or duration of the preheating treatment. If the temperature difference is greater than 0 (that is, the actual temperature is lower than the preset startup temperature), it is decided to perform preheating treatment, such as: internal heating element: an electric heating element integrated inside the controller, which is automatically turned on when or before the controller is started to raise the internal temperature of the controller to a preset level; external heat source: such as using a hot air blower or a heating blanket to preheat the controller, thereby improving the preheating treatment efficiency and startup performance of the duty cycle variable frequency controller in a low temperature environment.

[0042] Optionally, the output load value is converted into a corresponding pulse width modulation signal, and then the duty cycle amplitude coefficient is obtained according to the proportion of the high level signal and the low level signal in the pulse width modulation signal within a preset period; the duty cycle amplitude coefficient is the sum of the high level amplitude coefficient and the low level amplitude coefficient, the high level amplitude coefficient is used to measure the continuous proportion of the high level signal within the preset period, and the low level amplitude coefficient is used to measure the continuous proportion of the low level signal within the preset period; the duty cycle amplitude coefficient is calculated by the following formula:

[0043] ;

[0044] ;

[0045] ;

[0046] Where y is the number of the preset cycle, , Q is the total number of preset cycles, g is the number of high-level signals, , G is the total number of high-level signals, d is the number of low-level signals, , D is the total number of low-level signals, e is a natural constant, represents the duty cycle amplitude coefficient of the pulse width modulation signal in the yth preset period, represents the high level amplitude coefficient of the high level signal in the pulse width modulation signal in the yth preset period, represents the low-level amplitude coefficient of the low-level signal in the pulse width modulation signal in the y-th preset period, represents the high-level signal duration of the g-th high-level signal in the pulse width modulation signal within the y-th preset period, Indicates the reference duration of the high level signal. Indicates the high level signal duration correction factor, represents the low-level signal duration of the d-th low-level signal in the pulse width modulation signal within the y-th preset cycle, Indicates the reference duration of the low level signal. Represents the low-level signal duration correction factor; the high-level signal duration correction factor and the low-level signal duration correction factor are obtained from a preset database, the high-level signal duration correction factor is used to correct the waveform of the high-level signal within a preset period, and the low-level signal duration correction factor is used to correct the waveform of the low-level signal within a preset period.

[0047] In this embodiment, the high level duty cycle D is the high level time The ratio of the total cycle time T, where The high-level duty cycle amplitude coefficient is usually obtained by multiplying the reference value of the high-level duty cycle by the high-level duty cycle, wherein the reference value of the high-level duty cycle is usually represented by the sum and average of the high-level duty cycle data in the preset database. Through the above method, the low-level duty cycle amplitude coefficient can also be obtained; the high-level signal reference duration is usually represented by the sum and average of the high-level duration data in the preset database, and the low-level signal reference duration is usually represented by the sum and average of the low-level duration data in the preset database.

[0048] It should be understood that the high-level signal duration correction factor is obtained from a preset database. In a specific embodiment, the relationship between the high-level signal duration coefficient and the high-level amplitude coefficient is fitted by fitting the historical high-level signals in the preset database and the duration of the high level in a preset time period to obtain a fitting curve, the relationship between the high-level signal duration and the high-level amplitude coefficient is determined according to the fitting curve, and the duration of the real-time high-level signal in the preset time period is substituted into the fitting curve to obtain the corresponding high-level signal duration correction factor, wherein the high-level duration coefficient represents the ratio of the absolute value of the difference between the high-level signal duration and the high-level signal reference duration to the high-level signal reference duration.

[0049] The low-level signal duration correction factor is obtained from a preset database. In a specific embodiment, the relationship between the low-level signal duration coefficient and the low-level amplitude coefficient is fitted by fitting the historical low-level signals in the preset database and the duration of the low level in the preset time period to obtain a fitting curve, the relationship between the low-level signal duration and the low-level amplitude coefficient is determined according to the fitting curve, and the duration of the real-time low-level signal in the preset time period is substituted into the fitting curve to obtain the corresponding low-level signal duration correction factor, wherein the low-level duration coefficient represents the ratio of the absolute value of the difference between the duration of the low-level signal and the reference duration of the low-level signal to the reference duration of the low-level signal, thereby achieving an improvement in the efficiency of adjusting the output duty cycle of the duty cycle variable frequency controller in the preset time period, and effectively solving the problem of low efficiency of adjusting the output duty cycle of the duty cycle variable frequency controller in the preset time period in the prior art.

[0050] Optionally, the specific steps of mapping the output load value within a preset time period to the output duty cycle of the pulse width modulation signal include: obtaining in real time the time period in which the output load value increases within the preset cycle and obtaining the high-level duty cycle in combination with the duration of the high-level signal, and simultaneously obtaining in real time the time period in which the output load value decreases within the preset cycle and obtaining the low-level duty cycle in combination with the duration of the low-level signal, the high-level duty cycle represents the ratio of the duration of the high-level signal to the preset time period, and the low-level duty cycle represents the ratio of the duration of the low-level signal to the preset time period; generating a corresponding pulse width modulation signal according to the obtained high-level duty cycle and low-level duty cycle, and simultaneously monitoring the frequency change trend of the pulse width modulation signal within the preset cycle in real time according to the amplitude signals of the high-level signal and the low-level signal, the amplitude signal is used to reflect the peak values ​​of the high-level signal and the low-level signal within the preset cycle.

[0051] In this embodiment, a sensor is used to monitor the output load value in real time, and the load value and sampling time of each sampling point are recorded. Within a preset period, the time period when the load value increases and the time period when the load value decreases are recorded. Usually, the high-level duty cycle is obtained by the ratio of the time period when the load value increases to the preset period, and the low-level duty cycle is obtained by the ratio of the time period when the load value decreases to the preset period. It should be noted that in standard PWM control, usually only the high-level duty cycle is concerned, because the low-level duty cycle is automatically determined by subtracting the high-level time from the cycle length, and a square wave signal (i.e., a PWM signal) with a desired duty cycle is generated based on the calculated high-level duty cycle and low-level duty cycle and through a dedicated PWM generator.

[0052] Specifically, when the sensor detects the rising edge of the PWM signal (from low level to high level), the timer is started. When the sensor detects the next falling edge (from high level to low level), the timer is stopped and the time difference is recorded. This is the length of one cycle (i.e., the preset cycle). The frequency of the PWM signal refers to the number of times the PWM cycle (a complete combination of high level and low level) is repeated per unit time. The changing trend of the frequency of the PWM signal within the preset cycle usually includes an increase or decrease in frequency, a periodic change in frequency, and a sudden change in frequency. For example, in a motor control system, in order to adjust the speed of the motor, it is usually achieved by changing the frequency of the PWM signal. An increase in frequency may mean that the motor needs to accelerate, while a decrease in frequency may mean that the motor needs to decelerate. In the simulation of audio signals, the frequency change of the PWM signal can simulate the pitch change of the sound. Similarly, in motor speed regulation, by accurately controlling the frequency change of the PWM signal, smooth acceleration and deceleration of the motor can be achieved, and the accuracy of the output duty cycle of the pulse width modulation signal is improved.

[0053] Optionally, obtaining the level proportion degree also includes real-time monitoring of the change of the high level duty cycle and the low level duty cycle in the pulse width modulation signal within a preset period. When the high level duty cycle is not greater than the low level duty cycle, the output load value of the duty cycle frequency conversion controller within a preset time period is obtained, otherwise the level proportion degree is calculated by the following formula:

[0054] ;

[0055] Where y is the number of the preset cycle, , Q is the total number of preset cycles, g is the number of high-level signals, , G is the total number of high-level signals, d is the number of low-level signals, , D is the total number of low-level signals, e is a natural constant, Indicates the level proportion of the pulse width modulation signal in the yth preset cycle, represents the high level duty cycle of the g-th high level signal in the pulse width modulation signal in the y-th preset period, Indicates the high level reference duty cycle, represents the low-level duty cycle of the d-th low-level signal in the pulse width modulation signal within the y-th preset period, Indicates the low level reference duty cycle.

[0056] In this embodiment, in order to simplify the analysis, we define , , where represents the high-level duty cycle coefficient of the high-level signal in the pulse width modulation signal in the y-th preset period, The low-level duty cycle coefficient of the low-level signal in the pulse width modulation signal in the y-th preset cycle is represented by the simplified calculation formula of the level proportion: ,in, , the statistical table of changes in the level proportion is shown in Table 1:

[0057] Table 1 Statistics of changes in level proportion

[0058]

[0059] It should be understood that the high-level reference duty cycle is usually represented by the sum and average of the high-level duty cycle data in the preset database, and the low-level reference duty cycle is usually represented by the sum and average of the low-level duty cycle data in the preset database, thereby improving the accuracy and reliability of obtaining the level proportion degree, and further improving the efficiency of adjusting the output duty cycle of the duty cycle frequency converter within the preset time period, effectively solving the problem of low efficiency of adjusting the output duty cycle of the duty cycle frequency converter within the preset time period in the prior art.

[0060] Optionally, the acquired high-level proportion is input into a PID control algorithm set in the duty cycle frequency conversion controller for closed-loop feedback, which also includes configuring the control parameters of the PID control algorithm in the duty cycle frequency conversion controller. The control parameters include a proportional coefficient, an integral coefficient and a differential coefficient. The proportional coefficient is used to adjust the proportional relationship between the output of the duty cycle frequency conversion controller and the controlled quantity deviation. The integral coefficient is used to eliminate the steady-state error of the duty cycle frequency conversion controller. The differential coefficient is used to predict the changing trend of the steady-state error within a preset time period.

[0061] In this embodiment, the proportional coefficient is used to adjust the proportional relationship between the output of the duty cycle frequency conversion controller and the deviation of the controlled quantity. When there is a deviation between the controlled quantity (the output duty cycle of the duty cycle frequency conversion controller) and the set value, the proportional term will immediately produce a control effect proportional to the deviation to reduce the deviation. Increasing the proportional coefficient can speed up the response speed of the duty cycle frequency conversion controller and reduce the steady-state error. The integral coefficient is used to eliminate the steady-state error of the duty cycle frequency conversion controller. During the control process, if there is a continuous deviation in the system (i.e., steady-state error), the integral term will continuously accumulate these deviations and adjust the output. (output duty cycle) to gradually reduce the deviation until the deviation is zero; the differential coefficient is used to predict the changing trend of the steady-state error within a preset time period. The differential term can reflect the future changing trend of the deviation by obtaining the differential information of the deviation (i.e., the rate of change of the deviation). Before the deviation is formed, the differential term can produce a control effect, thereby accelerating the response speed of the duty cycle frequency conversion controller and reducing overshoot and oscillation; in practical applications, the trial and error method and the empirical formula method can be used to adjust the PID parameters according to the specific characteristics and requirements of the system, thereby improving the accuracy of the control parameter setting of the PID control algorithm.

[0062] Optionally, the specific steps of converting the feedback signal into a feedback value and comparing it with a target value to obtain an error rate include: performing digital signal processing on the obtained feedback signal to obtain a feedback value and measuring the signal-to-noise ratio of the feedback value through a signal processor, the digital signal processing includes numerical conversion, filtering processing and denoising processing, and the signal-to-noise ratio is used to reflect the degree of influence of noise on the feedback value within a preset time; obtaining a delay rate according to the sending time and receiving time of the feedback value within a preset time period and performing delay compensation, and at the same time obtaining the error rate in combination with the obtained signal-to-noise ratio, the delay rate represents the ratio of the absolute value of the difference between the receiving time and the sending time to the sending time.

[0063] In this embodiment, the obtained feedback signal is usually an analog signal, which needs to be sampled and quantized and converted into a digital signal (i.e., feedback value) through an analog-to-digital converter. The noise frequency and DC component in the feedback signal are removed by a band-stop filter in a digital filter so that it fluctuates around a zero mean value. Sampling is the process of converting a continuous-time signal into a discrete-time signal, and quantization is the process of converting the amplitude value of the signal into a finite number (i.e., the number required for the closed-loop control output duty cycle) of discrete values. Sampling and quantization jointly determine the resolution and accuracy of the digital signal. The signal processor usually obtains the signal-to-noise ratio by measuring the power and noise power of the feedback signal in a preset time period. The specific calculation formula is: , where is the signal-to-noise ratio of the feedback signal, is the power of the feedback signal, It is the noise power of the noise signal in the feedback signal. In digital signal processing, it can be approximated by calculating the sum of squares or the average of squares of the feedback signal. In practical applications, the time delay rate is obtained by the sending time and receiving time of the feedback value within a preset time period, where the time delay rate represents the ratio of the absolute value of the difference between the receiving time and the sending time to a preset time period (such as 1 second, 10 seconds, or 1 minute).

[0064] Specifically, the error rate is calculated by the following formula:

[0065] ;

[0066] Where t is the number of the preset time period, , T is the total number of preset time periods, y is the number of the preset period, , Q is the total number of preset cycles, represents the error rate of the feedback signal in the t-th preset time period in the y-th preset period, represents the signal-to-noise ratio of the feedback signal in the t-th preset time period in the y-th preset period, represents the reference signal-to-noise ratio, represents the delay rate of the feedback signal in the t-th preset time period in the y-th preset period, Indicates the reference delay rate.

[0067] Specifically, to simplify the analysis, we define , , where express, The simplified calculation formula of the error rate is: , wherein the reference signal-to-noise ratio is usually represented by the sum and average of the signal-to-noise ratio data in the preset database, and the reference delay rate is usually represented by the sum and average of the delay data in the preset database, such as Figure 2 As shown, it is a three-dimensional coordinate analysis diagram of the error rate provided by an embodiment of the present invention. It can be seen from the figure that when the signal-to-noise ratio coefficient and the delay rate coefficient are in the range of 0.2 to 1, the error rate decreases with the increase of the signal-to-noise ratio coefficient, and increases with the increase of the delay rate coefficient.

[0068] It should be understood that the algorithm of this embodiment combines the signal-to-noise ratio coefficient and the delay rate coefficient factors, and obtains the error rate through comprehensive analysis. The signal-to-noise ratio and the delay rate in this formula not only unilaterally affect the value of the error rate, but the signal-to-noise ratio also indirectly affects the value of the delay rate. For example, in a communication system, the accuracy and real-time performance of data transmission are very important. When the signal-to-noise ratio is low, even if the delay rate is very low, the error rate of data transmission will increase due to the interference of noise on the signal. Similarly, when the delay rate is high, even if the signal-to-noise ratio is very high, the overall performance of the system will be affected because the data needs to wait for a long time during transmission or processing, thereby improving the accuracy and reliability of error rate acquisition.

[0069] Optionally, the feedback signal is converted into a feedback value and compared with a target value to obtain an error rate, and then the control items corresponding to the control parameters of the PID control algorithm are added and combined with the obtained error rate to obtain the total output of the PID control algorithm. The control items include proportional items, integral items and differential items. The total output of the PID control algorithm is used to reflect the control of the output error rate by the PID control algorithm within a preset time period. The specific calculation formula for the total output of the PID control algorithm is:

[0070] ;

[0071] Where t is the number of the preset time period, , T is the total number of preset time periods, is the tth preset time period, ,in is any point in the tth preset time period, y is the number of the preset period, , Q is the total number of preset cycles, represents the total output of the PID control algorithm in the tth preset time period, represents the error rate of the feedback signal in the t-th preset time period in the y-th preset period, represents the proportionality constant, represents the integration constant, represents the differential constant.

[0072] In this embodiment, the feedback signal is usually the original signal directly obtained from the output end of the control system in the duty cycle frequency conversion controller, and the feedback value is obtained from the original signal through conversion (such as scaling, offset and filtering). For example, if the feedback signal is an analog voltage signal and position information is required, it needs to be converted into a position value through an appropriate circuit (such as an analog-to-digital converter, a proportional amplifier); the target value is usually the output value that the control system expects to achieve, which is a known, preset value. The error rate is the difference between the target value and the feedback value, which is used to measure the deviation between the current output of the control system and the target output. In a temperature control system, the target temperature is set to , and the current temperature of the system (measured by the temperature sensor and converted into a digital value) is Y(t). If the feedback value obtained after the conversion of Y(t) is , then the error rate e(t) is , this error rate e(t) will be used as the input of the PID control algorithm to adjust the control input of the system, thereby reducing or eliminating the error and making the system output close to the target value, thereby improving the output efficiency and accuracy of the PID control algorithm, and further improving the duty cycle adjustment efficiency of the duty cycle variable frequency controller within the preset time period, effectively solving the problem of low output duty cycle adjustment efficiency of the duty cycle variable frequency controller within the preset time period in the prior art.

[0073] Optionally, the specific steps of closed-loop feedback are: converting the acquired total output of the PID control algorithm into a duty cycle signal, and at the same time limiting the total output of the PID control algorithm according to the dynamic response characteristics of the duty cycle frequency converter, the duty cycle signal is used to reflect the high and low output frequency of the duty cycle frequency converter within a preset time period, and the limiting processing is used to prevent abnormal fluctuations in the output duty cycle of the duty cycle frequency converter within a preset time period; dynamically adjusting the output frequency of the duty cycle frequency converter according to the result of the limiting processing and the duty cycle signal, and the steps of dynamic adjustment are: increasing the output response speed of the PID control algorithm when the output load value increases, and reducing the output response speed of the PID control algorithm when the output load value decreases.

[0074] In this embodiment, the total output of the PID control algorithm is a continuously changing signal, which may represent a control variable such as voltage, current, position, etc. The effective range of the PID output u(t) is determined according to the requirements of the control system in the duty cycle variable frequency controller and the limitations of the hardware. For example, if the PID output is used to control the speed of the motor, then the output range may be the voltage or current value corresponding to the motor speed from 0 to 100%; the effective range of the PID output is mapped to the effective range of the duty cycle signal (usually a duty cycle of 0% to 100%), which usually requires a linear or nonlinear mapping function, and then a PWM (pulse width modulation) technique is used to generate a duty cycle signal, the ratio of its high level time (i.e., pulse width) to the cycle time is equal to the required duty cycle; assuming that the maximum duty cycle of the PWM driver is 100% and the minimum duty cycle is 0%, a simple linear mapping function can be used to directly map the value of u(t) to the duty cycle range: ,if , the calculated duty cycle is 50%, and the high level time of the PWM signal will account for half of the entire cycle time. This duty cycle value is input into the PWM generator to generate the corresponding duty cycle signal, which is applied to the motor driver to control the speed of the motor.

[0075] Specifically, a limiter is inserted between the output of the PID controller and the input of the variable frequency controller. The function of the limiter is to limit the output of the PID controller within the effective range acceptable to the variable frequency controller. If the PID output exceeds the upper limit: set the PID output to the upper limit value (for example, if the upper limit is 100% duty cycle, any PID output greater than 100% will be truncated to 100%); if the PID output is lower than the lower limit: set the PID output to the lower limit value (for example, if the lower limit is 0% duty cycle, any PID output less than 0% will be truncated to 0%); when the output load value increases: improve the output response speed of the PID control algorithm: this usually means increasing the proportional gain Kp to reduce the time required to reach the set point. At the same time, you can consider reducing the integral time Ti to speed up the elimination of steady-state errors, but Integral saturation should also be avoided. The adjustment of the differential time Td is usually not so direct because it is mainly used to predict the changing trend of future errors. In some cases, increasing Td can improve the system's response speed to load changes, but it may also introduce noise sensitivity. When the output load value decreases: reduce the output response speed of the PID control algorithm: this usually means reducing the proportional gain Kp to increase the stability of the system and reduce overshoot. At the same time, you can consider increasing the integral time Ti to eliminate steady-state errors more smoothly and avoid excessive accumulation of integral terms. In actual application, it is necessary to integrate the above-mentioned response speed adjustment logic in the implementation of the PID controller, which usually involves adding additional code to the PID control loop to monitor changes in the output load value and adjust the PID parameters according to preset rules, thereby achieving more precise control of the output response rate of the PID control algorithm.

[0076] like Figure 3As shown, it is a structural schematic diagram of a control system for load self-adaptation during closed-loop startup of a frequency conversion controller provided by an embodiment of the present invention. A control system for load self-adaptation during closed-loop startup of a frequency conversion controller provided by an embodiment of the present invention comprises: a pulse width modulation signal acquisition module, a level proportion acquisition module, a feedback signal acquisition module and a closed-loop feedback module; wherein the pulse width modulation signal acquisition module is used to acquire the output load value of the duty cycle frequency conversion controller within a preset time period, and at the same time convert the output load value into a corresponding pulse width modulation signal, the output load value is used to reflect the load change of the duty cycle frequency conversion controller within the preset time period, and the pulse width The modulation signal includes a high-level signal, a low-level signal and an equal-level signal. The high-level signal is used to reflect the process of the output load value increasing within a preset period, the low-level signal is used to reflect the process of the output load value decreasing within the preset period, and the equal-level signal is used to reflect the process of the output load value remaining unchanged within the preset period. The high-level signal is greater than the low-level signal. The level proportion degree acquisition module is used to map the output load value within a preset time period to the output duty cycle of the pulse width modulation signal to obtain the level proportion degree. The output duty cycle includes a high-level duty cycle and a low-level duty cycle. The high-level duty cycle is used to reflect the increase degree of the output load value within the preset period. The low-level duty cycle is used to reflect the degree of reduction of the output load value within the preset period, and the level proportion is used to measure the proportion of the high-level duty cycle and the low-level duty cycle in the output duty cycle within the preset period; the feedback signal acquisition module is used to monitor the change of the output duty cycle of the pulse width modulation signal in real time, and at the same time input the acquired level proportion into the PID control algorithm set in the duty cycle frequency conversion controller to obtain the feedback signal. The feedback signal is the output duty cycle change amount that the PID control algorithm needs to adjust; the closed-loop control module is used to convert the feedback signal into a feedback value and compare it with the target value to obtain the error rate, and perform closed-loop feedback at the same time And determine whether the output duty cycle of the closed-loop feedback meets the preset duty cycle error threshold. If so, record the current operating status and output duty cycle of the duty cycle frequency converter and feed back to the preset management personnel. Otherwise, re-closed-loop feedback is performed until the output duty cycle of the closed-loop feedback meets the preset duty cycle error threshold. The target value is the duty cycle corresponding to the preset output power. The error rate is used to measure the degree of deviation between the feedback value and the target value. The closed-loop feedback is used to adjust the output duty cycle of the pulse width modulation signal in real time according to the control parameters of the PID control algorithm. The duty cycle error threshold represents the difference between the maximum allowable error and the minimum allowable error of the closed-loop feedback output duty cycle.

[0077] In this embodiment, the duty cycle error threshold is usually represented by the result of summing and averaging the duty cycle error data in the preset database, and usually represents the maximum deviation between the output duty cycle acceptable to the closed-loop feedback module and the target value. This threshold is determined by the minimum allowable error and the maximum allowable error, and the difference is the threshold width; the PID control algorithm is used to adjust the output duty cycle of the pulse width modulation (PWM) signal according to the error rate to reduce the error rate so that the actual output gradually approaches the target value. After each adjustment, the current duty cycle is re-compared with the target value to determine whether the error has been reduced to within the preset duty cycle error threshold. If the error threshold condition is met, it is considered that the system has reached a stable state, and the current operating state and output duty cycle can be recorded, and feedback is sent to the preset management personnel. If the output duty cycle does not meet the error threshold condition, the closed-loop feedback process is continued, the error rate is recalculated and the duty cycle of the PWM signal is adjusted until the error rate is reduced to an acceptable range, thereby improving the accuracy and reliability of the output duty cycle closed-loop output and feedback.

[0078] There are a few points to note:

[0079] (1) The drawings of the embodiments of the present invention only involve structures related to the embodiments of the present invention. Other structures may refer to conventional designs.

[0080] (2) For the sake of clarity, in the drawings used to describe the embodiments of the present invention, the thickness of layers or regions is exaggerated or reduced, that is, these drawings are not drawn according to the actual scale. It is understood that when an element such as a layer, film, region or substrate is referred to as being "on" or "under" another element, the element may be "directly" "on" or "under" the other element or there may be intermediate elements.

[0081] (3) In the absence of conflict, the embodiments of the present invention and the features therein may be combined with each other to obtain new embodiments.

[0082] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. The protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A load adaptive control method for closed-loop startup of a frequency conversion controller, characterized in that: The following steps are involved: S1, obtaining an output load value of the duty cycle frequency conversion controller within a preset time period, and converting the output load value into a corresponding pulse width modulation signal, wherein the output load value is used to reflect the load change of the duty cycle frequency conversion controller within the preset time period, and the pulse width modulation signal includes a high level signal, a low level signal and an equal level signal; S2, mapping the output load value within the preset time period to the output duty cycle of the pulse width modulation signal to obtain a level proportion, wherein the output duty cycle includes a high level duty cycle and a low level duty cycle, and the level proportion is used to measure the proportion of the high level duty cycle and the low level duty cycle in the output duty cycle within the preset period; S3, real-time monitoring of the change of the output duty cycle of the pulse width modulation signal, and inputting the acquired level proportion into the PID control algorithm set in the duty cycle frequency conversion controller to obtain a feedback signal, wherein the feedback signal is the output duty cycle change amount that needs to be adjusted by the PID control algorithm; S4, converts the feedback signal into a feedback value and compares it with the target value to obtain the error rate, and performs closed-loop feedback and determines whether the output duty cycle of the closed-loop feedback meets the preset duty cycle error threshold. If so, the current operating status and output duty cycle of the duty cycle frequency converter are recorded and fed back to the preset management personnel. The error rate is used to measure the degree of deviation between the feedback value and the target value.

2. The load adaptive control method during closed-loop startup of a frequency conversion controller according to claim 1 is characterized in that: The step of obtaining the output load value of the duty cycle frequency conversion controller within a preset time period also includes preheating the duty cycle frequency conversion controller before startup. The specific process is as follows: The actual temperature before the duty cycle frequency conversion controller is started in a preset low temperature environment is measured by a temperature sensor and compared with the preset starting temperature to obtain the temperature difference; The corresponding preheating value is set according to the obtained temperature difference value and the duty cycle frequency conversion controller is started within the unit preheating time until the temperature generated by the heating element in the duty cycle frequency conversion controller is equal to the preset starting temperature.

3. The load adaptive control method during closed-loop startup of a frequency conversion controller according to claim 1 is characterized in that: The step of converting the output load value into a corresponding pulse width modulation signal further includes obtaining a duty cycle amplitude coefficient according to the pulse width modulation signal; The duty cycle amplitude coefficient is the sum of the high level amplitude coefficient and the low level amplitude coefficient, the high level amplitude coefficient is used to measure the continuous proportion of the high level signal in a preset period, and the low level amplitude coefficient is used to measure the continuous proportion of the low level signal in a preset period; The duty cycle amplitude factor is calculated by the following formula: ； ； ； Where y is the number of the preset cycle, , Q is the total number of preset cycles, g is the number of high-level signals, , G is the total number of high-level signals, d is the number of low-level signals, , D is the total number of low-level signals, e is a natural constant, represents the duty cycle amplitude coefficient of the pulse width modulation signal in the yth preset period, represents the high-level amplitude coefficient of the high-level signal in the pulse width modulation signal in the y-th preset period, represents the low-level amplitude coefficient of the low-level signal in the pulse width modulation signal in the y-th preset period, represents the high-level signal duration of the g-th high-level signal in the pulse width modulation signal within the y-th preset period, Indicates the reference duration of the high level signal. Indicates the high level signal duration correction factor, represents the low-level signal duration of the d-th low-level signal in the pulse width modulation signal within the y-th preset cycle, Indicates the reference duration of the low level signal. Indicates the low-level signal duration correction factor.

4. The load adaptive control method during closed-loop startup of a frequency conversion controller according to claim 1 is characterized in that: The specific steps of mapping the output load value within the preset time period to the output duty cycle of the pulse width modulation signal include: Real-time acquisition of the time period during which the output load value increases within a preset period and combines the duration of the high-level signal to obtain the high-level duty cycle, and real-time acquisition of the time period during which the output load value decreases within the preset period and combines the duration of the low-level signal to obtain the low-level duty cycle; A corresponding pulse width modulation signal is generated according to the acquired high level duty cycle and low level duty cycle, and at the same time, a frequency change trend of the pulse width modulation signal within a preset period is monitored in real time according to the amplitude signals of the high level signal and the low level signal.

5. The load adaptive control method during closed-loop startup of a frequency conversion controller according to claim 1 is characterized in that: The acquisition of the level proportion degree also includes real-time monitoring of the changes in the high-level duty cycle and the low-level duty cycle in the pulse width modulation signal within a preset period. When the high-level duty cycle is not greater than the low-level duty cycle, the output load value of the duty cycle frequency conversion controller within a preset time period is obtained, otherwise the level proportion degree is calculated by the following formula: ； Where y is the number of the preset cycle, , Q is the total number of preset cycles, g is the number of high-level signals, , G is the total number of high-level signals, d is the number of low-level signals, , D is the total number of low-level signals, e is a natural constant, Indicates the level proportion of the pulse width modulation signal in the yth preset cycle, represents the high level duty cycle of the g-th high level signal in the pulse width modulation signal in the y-th preset period, Indicates the high level reference duty cycle, represents the low-level duty cycle of the d-th low-level signal in the pulse width modulation signal within the y-th preset period, Indicates the low level reference duty cycle.

6. The method for controlling load adaptation during closed-loop startup of a frequency conversion controller according to claim 1, characterized in that: The acquired high level proportion is input into the PID control algorithm set in the duty cycle frequency conversion controller for closed-loop feedback, which also includes configuring the control parameters of the PID control algorithm in the duty cycle frequency conversion controller, and the control parameters include proportional coefficient, integral coefficient and differential coefficient.

7. The load adaptive control method during closed-loop startup of a frequency conversion controller according to claim 1 is characterized in that: The specific steps of converting the feedback signal into a feedback value and comparing it with a target value to obtain an error rate include: Performing digital signal processing on the acquired feedback signal to obtain a feedback value and measuring a signal-to-noise ratio of the feedback value through a signal processor; The delay rate is obtained according to the sending time and receiving time of the feedback value within the preset time period, and the error rate is obtained by combining the obtained signal-to-noise ratio; The error rate is calculated by the following formula: ； Where t is the number of the preset time period, , T is the total number of preset time periods, y is the number of the preset period, , Q is the total number of preset cycles, represents the error rate of the feedback signal in the t-th preset time period in the y-th preset period, represents the signal-to-noise ratio of the feedback signal in the t-th preset time period in the y-th preset period, represents the reference signal-to-noise ratio, represents the delay rate of the feedback signal in the t-th preset time period in the y-th preset period, Indicates the reference delay rate.

8. The load adaptive control method during closed-loop startup of a frequency conversion controller according to claim 1 is characterized in that: The feedback signal is converted into a feedback value and compared with a target value to obtain an error rate, and then the control items corresponding to the control parameters of the PID control algorithm are added and combined with the obtained error rate to obtain the total output of the PID control algorithm, wherein the control items include proportional items, integral items and differential items. The total output of the PID control algorithm is used to reflect the control of the output error rate by the PID control algorithm within a preset time period. The specific calculation formula of the total output of the PID control algorithm is: ； Where t is the number of the preset time period, , T is the total number of preset time periods, is the tth preset time period, ,in is any point in the tth preset time period, y is the number of the preset period, , Q is the total number of preset cycles, represents the total output of the PID control algorithm in the tth preset time period, represents the error rate of the feedback signal in the t-th preset time period in the y-th preset period, represents the proportionality constant, represents the integration constant, represents the differential constant.

9. The load adaptive control method during closed-loop startup of a frequency conversion controller according to claim 8, characterized in that: The specific steps of the closed-loop feedback are: The total output of the acquired PID control algorithm is converted into a duty cycle signal, and the total output of the PID control algorithm is limited according to the dynamic response characteristics of the duty cycle frequency conversion controller, wherein the limiting process is used to prevent the duty cycle of the duty cycle frequency conversion controller from fluctuating abnormally within a preset time period; The output frequency of the duty cycle variable frequency controller is dynamically adjusted according to the result of the limiting processing and the duty cycle signal.

10. A load adaptive control system for closed-loop startup of a frequency conversion controller, characterized in that: include: Pulse width modulation signal acquisition module, level proportion acquisition module, feedback signal acquisition module and closed-loop feedback module; The pulse width modulation signal acquisition module is used to acquire the output load value of the duty cycle frequency conversion controller within a preset time period, and convert the output load value into a corresponding pulse width modulation signal. The output load value is used to reflect the load change of the duty cycle frequency conversion controller within a preset time period. The pulse width modulation signal includes a high level signal, a low level signal and an equal level signal. The level proportion acquisition module is used to map the output load value within a preset time period to the output duty cycle of the pulse width modulation signal to obtain the level proportion, wherein the output duty cycle includes a high level duty cycle and a low level duty cycle, and the level proportion is used to measure the proportion of the high level duty cycle and the low level duty cycle in the output duty cycle within a preset period; The feedback signal acquisition module is used to monitor the change of the output duty cycle of the pulse width modulation signal in real time, and input the acquired level proportion into the PID control algorithm set in the duty cycle frequency conversion controller to obtain a feedback signal, and the feedback signal is the output duty cycle change amount that the PID control algorithm needs to adjust; The closed-loop control module is used to convert the feedback signal into a feedback value and compare it with the target value to obtain the error rate. At the same time, closed-loop feedback is performed and it is determined whether the output duty cycle of the closed-loop feedback meets the preset duty cycle error threshold. If so, the current operating status and output duty cycle of the duty cycle frequency converter are recorded and fed back to the preset management personnel. The error rate is used to measure the degree of deviation between the feedback value and the target value.

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