Disclosure of Invention
Aiming at the defects in the prior art, the high-frequency digital direct-current power supply driving method provided by the invention solves the problems that the traditional high-frequency digital direct-current power supply driving method is highly dependent on pole-free analysis and solidification design of an analog electronic circuit, has poor flexibility, is easily influenced by load parasitic parameters, and is not easy to dynamically adjust such as safety control according to the load electrifying condition.
In order to achieve the aim of the invention, the invention adopts the following technical scheme: a high frequency digital DC power supply driving method comprises the following steps:
calculating a theoretical duty ratio according to the target value of the output voltage and the input voltage of the direct-current power supply, and generating a high-frequency digital pulse wave with the duty ratio being the theoretical duty ratio to initially drive the direct-current power supply;
calculating a voltage target difference between the output voltage of the direct current power supply and an output voltage target value;
and calculating and adjusting the duty ratio of the high-frequency digital pulse wave through the self-adaptive fuzzy control model according to the voltage target difference value and the load current, and driving the direct-current power supply.
The beneficial effects of the invention are as follows: according to the invention, through the self-adaptive fuzzy control model, on the basis of the high-frequency digital pulse wave preliminary driving direct-current power supply with the duty ratio being the theoretical duty ratio, the direct-current power supply is subjected to dynamic feedback adjustment by utilizing the error of the output voltage and the current state of the load, so that the direct-current power supply can be adapted to various loads, and is stable and safe in output, high in flexibility, strong in robustness and good in safety.
Further, the method for calculating the theoretical duty ratio according to the target value of the output voltage and the input voltage of the direct current power supply comprises the following steps:
calculating a theoretical duty ratio through a first duty ratio calculation equation according to the output voltage target value and the input voltage of the direct current power supply;
setting a simulation test of a high-frequency digital pulse wave driving direct-current power supply with a duty ratio being a theoretical duty ratio;
if the current existence value of the power inductor flowing through the direct current power supply is 0 in the simulation test, the theoretical duty ratio is correct;
if the current flowing through the power inductor in the direct current power supply does not have the value of 0 in the simulation test, the theoretical duty cycle is recalculated through the second duty cycle calculation equation.
Further, the first duty ratio calculation equation is:
wherein,,is duty cycle, +.>Is the input voltage of the DC power supply, +.>Is the output voltage target value.
Further, the second duty ratio calculation equation is:
wherein,,is duty cycle, +.>Is the period value of the high frequency digital pulse wave, +.>For the power inductance value>Is the resistance value of the load.
The beneficial effects of the above-mentioned further scheme are: in the dc power supply using the switching power supply technology, when the high frequency digital pulse wave is not matched with the power inductor, that is, when the frequency of the high frequency digital pulse wave is too small or the power inductance value is too small, the current attenuation of 0 flowing through the power inductor occurs during the process of turning on and off the power switching element. At this time, the electrical characteristics will change, the relation between the output voltage and the input voltage of the direct current power supply will not be determined only by the duty ratio of the high frequency digital pulse wave, and the cycle value, the power inductance value and the load condition of the high frequency digital pulse wave need to be considered to perform complete modeling on the input and output voltages, and the duty ratio is recalculated. If the direct current power supply is driven by directly using an empirical formula in the prior art, namely a first duty ratio calculation equation, the direct current power supply and the load are damaged if the load is undervoltage and the system is unstable due to light weight and if the load is unstable due to heavy weight.
Further, the expression of the adaptive fuzzy control model is:
wherein,,for adaptive fuzzy control model +.>Duty cycle calculated at secondary adjustment, +.>For the outer ring +>Feedback value at sub-regulation,/->For the outer ring differential coefficient>For adaptive fuzzy control model +.>Duty cycle calculated at secondary adjustment, +.>For the outer ring +>Cache value at secondary adjustment, < >>Is->The voltage target difference at the time of the secondary adjustment,for the outer ring +>Feedback value at sub-regulation,/->For counting the number of historical adjustment times, +.>For the outer loop integration coefficient,for the outer ring scale factor, +.>Is an inner ring proportionality coefficient->Is->Voltage target difference at secondary regulation, +.>Is the inner ring->Feedback value at sub-regulation,/->Is the differential coefficient of the inner ring->Is the inner ring->Output at sub-adjustment, < >>Is the inner ringOutput at sub-adjustment, < >>For the inner loop integral coefficient, +.>For the outer ring +>Cache value at secondary adjustment, < >>Is the inner ring->Feedback value at sub-regulation,/->To adjust the coefficients.
The beneficial effects of the above-mentioned further scheme are: the built self-adaptive fuzzy control model is provided with an inner feedback loop and an outer feedback loop, integrates through the memory accumulation of past data, and performs double-loop proportional-integral-derivative control through the subtraction of current data and data of the past fuzzy control link. The outer ring makes the fuzzy control system converge towards stability, lays a control foundation with the residual difference of 0, and the inner ring carries out fine adjustment on the control quantity, increases damping, suppresses oscillation and accelerates the convergence of the fuzzy control system.
Further, an outer loop scaling factor in the adaptive fuzzy control modelInner ring scaling factor->Differential coefficient of outer ring->Differential coefficient of inner ring->Integration coefficient of outer ring->Inner loop integral coefficient->And adjustment coefficient->Mapping is carried out by adopting a coefficient model, wherein the coefficient model is as follows:
wherein,,is->Output of coefficient model at sub-adjustment, +.>Is->Output of coefficient model at sub-adjustment, +.>As hyperbolic tangent function, +.>To select weights, ++>Is->The first output weight at the time of the secondary adjustment,is->Second output weight at secondary adjustment, +.>Is->Third output weight at sub-adjustment, +.>Is->First output bias at sub-regulation, +.>Is->Second output bias at secondary adjustment, +.>Is->State quantity at secondary adjustment, +.>Is->Voltage target difference at secondary regulation, +.>Is->Load current value at sub-regulation, wherein +.>Output of coefficient model at sub-adjustment>The types of (2) include: external ring scaling factor->Inner ring scaling factor->Differential coefficient of outer ring->Differential coefficient of inner ring->Integration coefficient of outer ring->Inner loop integral coefficient->And adjustment coefficient->。
Further, the firstState quantity at sub-regulation->The formula of (2) is:
wherein,,is->Forgetfulness during secondary adjustment, +.>Is->Input during secondary adjustment, +.>Is->The state at the time of the secondary adjustment.
Further, the firstForgetfulness during secondary adjustment +.>The formula of (2) is:
wherein,,to activate the function +.>Is->Forgetting weight at secondary adjustment, +.>Is->Forgetting bias at secondary adjustment +.>Is->Voltage target difference at secondary regulation, +.>Is->Output of coefficient model at sub-adjustment, +.>Is->Load current value at the time of secondary adjustment.
Further, the firstInput at sub-setting ∈>The formula of (2) is:
wherein,,to activate the function +.>Is->First input weight at sub-adjustment, +.>Is->First input bias at sub-adjustment, +.>Is->Secondary adjustmentSecond input weight of whole time, +.>Is->Second input bias at secondary adjustment, +.>As hyperbolic tangent function, +.>Is->Voltage target difference at secondary regulation, +.>Is->Output of coefficient model at sub-adjustment, +.>Is->Load current value at the time of secondary adjustment.
The beneficial effects of the above-mentioned further scheme are: the load condition of the direct current power supply can directly influence the output state and the system stability of the direct current power supply, and even directly relate to the equipment safety of the direct current power supply. In order to improve the compatibility of a direct current power supply to a load without being influenced by parasitic parameters of the load, the self-adaptive fuzzy control model has self-adaptive capacity for adapting to the working state of the load, flexible adjustment of stability and safety is carried out, the time domain characteristics of the voltage target difference value and the load current value are extracted from a coefficient model with time domain memory, forgetting and updating functions on the voltage target difference value and the load current value, and the time domain characteristics are calculated and then used for adjusting each coefficient of the self-adaptive fuzzy control model, so that the problems that the prior art is highly dependent on analysis of a zero pole and solidification design of an analog electronic circuit, poor in flexibility, easy to be influenced by parasitic parameters of the load, and difficult to carry out dynamic adjustment such as safety control according to the electrifying condition of the load are solved.
Detailed Description
The following description of the embodiments of the present invention is provided to facilitate understanding of the present invention by those skilled in the art, but it should be understood that the present invention is not limited to the scope of the embodiments, and all the inventions which make use of the inventive concept are protected by the spirit and scope of the present invention as defined and defined in the appended claims to those skilled in the art.
In one embodiment of the present invention, a high frequency digital dc power driving method is used for driving a BUCK switching dc power supply, where the BUCK switching dc power supply is composed of a power switching element, a freewheel element, a power inductor and an energy storage capacitor, and mounts an electrical load. It is noted that, because the method is used for driving the direct current power supply, the BUCK switch direct current power supply is not provided with a special high-frequency digital pulse signal generator with a sampling feedback modulation function, and is replaced by a high-frequency digital pulse wave generating circuit with a configurable duty ratio, and the circuit is also in the prior art and is not repeated. As shown in fig. 1, the method comprises the following steps:
s1, calculating a theoretical duty ratio according to an output voltage target value and an input voltage of a direct current power supply, and generating a high-frequency digital pulse wave with the duty ratio being the theoretical duty ratio to initially drive the direct current power supply;
s2, calculating a voltage target difference value between the output voltage of the direct-current power supply and an output voltage target value;
s3, calculating and adjusting the duty ratio of the high-frequency digital pulse wave through the self-adaptive fuzzy control model according to the voltage target difference value and the load current, and driving the direct-current power supply.
In this embodiment, the present invention specifically includes:
a1, setting an input voltage safety interval, an output voltage target value, an abnormal output difference threshold value and a load current maximum jitter allowable value;
a2, judging whether the input voltage of the direct-current power supply is in an input voltage safety interval, if so, jumping to the step A3, and if not, jumping to the step A8;
a3, calculating a theoretical duty ratio according to the output voltage target value and the input voltage of the direct-current power supply, and generating a high-frequency digital pulse wave with the duty ratio being the theoretical duty ratio to initially drive the direct-current power supply;
a4, calculating a voltage target difference value between the output voltage of the direct-current power supply and an output voltage target value, judging whether the absolute value of the voltage target value is larger than an abnormal output difference threshold value, if so, jumping to the step A8, and if not, jumping to the step A5;
a5, calculating and adjusting the duty ratio of the high-frequency digital pulse wave through a self-adaptive fuzzy control model according to the voltage target difference value and the load current, and driving a direct-current power supply;
a6, monitoring the jitter value of the load current, judging whether the jitter value of the load current is larger than the maximum jitter allowable value of the load current, if so, jumping to the step A8, and if not, jumping to the step A7;
a7, judging whether the input voltage of the direct current power supply is in an input voltage safety interval, if so, jumping to the step A4, and if not, jumping to the step A8;
a8, turning off the direct current power supply.
In S1 or A3, according to the target value of the output voltage and the input voltage of the direct current power supply, the method for calculating the theoretical duty ratio is as follows:
calculating a theoretical duty ratio through a first duty ratio calculation equation according to the output voltage target value and the input voltage of the direct current power supply;
setting a simulation test of a high-frequency digital pulse wave driving direct-current power supply with a duty ratio being a theoretical duty ratio;
if the current existence value of the power inductor flowing through the direct current power supply is 0 in the simulation test, the theoretical duty ratio is correct;
if the current flowing through the power inductor in the direct current power supply does not have the value of 0 in the simulation test, the theoretical duty cycle is recalculated through the second duty cycle calculation equation.
The first duty cycle calculation equation is:
wherein,,is duty cycle, +.>Is the input voltage of the DC power supply, +.>Is the output voltage target value.
The second duty cycle calculation equation is:
wherein,,is duty cycle, +.>Is the period value of the high frequency digital pulse wave, +.>For the power inductance value>Is the resistance value of the load.
In the dc power supply using the switching power supply technology, when the high frequency digital pulse wave is not matched with the power inductor, that is, when the frequency of the high frequency digital pulse wave is too small or the power inductance value is too small, the current attenuation of 0 flowing through the power inductor occurs during the process of turning on and off the power switching element. At this time, the electrical characteristics will change, the relation between the output voltage and the input voltage of the direct current power supply will not be determined only by the duty ratio of the high frequency digital pulse wave, and the cycle value, the power inductance value and the load condition of the high frequency digital pulse wave need to be considered to perform complete modeling on the input and output voltages, and the duty ratio is recalculated. If the direct current power supply is driven by directly using an empirical formula in the prior art, namely a first duty ratio calculation equation, the direct current power supply and the load are damaged if the load is undervoltage and the system is unstable due to light weight and if the load is unstable due to heavy weight.
The expression of the adaptive fuzzy control model is as follows:
wherein,,for adaptive fuzzy control model +.>Duty cycle calculated at secondary adjustment, +.>For the outer ring +>Feedback value at sub-regulation,/->For the outer ring differential coefficient>For adaptive fuzzy control model +.>Duty cycle calculated at secondary adjustment, +.>For the outer ring +>Cache value at secondary adjustment, < >>Is->The voltage target difference at the time of the secondary adjustment,for the outer ring +>Feedback value at sub-regulation,/->For counting the number of historical adjustment times, +.>For the outer loop integration coefficient,for the outer ring scale factor, +.>Is an inner ring proportionality coefficient->Is->Voltage target difference at secondary regulation, +.>Is the inner ring->Feedback value at sub-regulation,/->Is the differential coefficient of the inner ring->Is the inner ring->Output at sub-adjustment, < >>Is the inner ringOutput at sub-adjustment, < >>For the inner loop integral coefficient, +.>For the outer ring +>Cache value at secondary adjustment, < >>Is the inner ring->Feedback value at sub-regulation,/->To adjust the coefficients.
The built self-adaptive fuzzy control model is provided with an inner feedback loop and an outer feedback loop, integrates through the memory accumulation of past data, and performs double-loop proportional-integral-derivative control through the subtraction of current data and data of the past fuzzy control link. The outer ring makes the fuzzy control system converge towards stability, lays a control foundation with the residual difference of 0, and the inner ring carries out fine adjustment on the control quantity, increases damping, suppresses oscillation and accelerates the convergence of the fuzzy control system.
Outer loop scaling factor in adaptive fuzzy control modelInner ring scaling factor->Differential coefficient of outer ring->Differential coefficient of inner ring->Integration coefficient of outer ring->Inner loop integral coefficient->And adjustment coefficient->Mapping is carried out by adopting a coefficient model, wherein the coefficient model is as follows:
wherein,,is->Output of coefficient model at sub-adjustment, +.>Is->Output of coefficient model at sub-adjustment, +.>As hyperbolic tangent function, +.>To select weights, ++>Is->The first output weight at the time of the secondary adjustment,is->Second output weight at secondary adjustment, +.>Is->Third output weight at sub-adjustment, +.>Is->First output bias at sub-regulation, +.>Is->Second output bias at secondary adjustment, +.>Is->State quantity at secondary adjustment, +.>Is->Voltage target difference at secondary regulation, +.>Is->Load current value at sub-regulation, wherein +.>Output of coefficient model at sub-adjustment>The types of (2) include: external ring scaling factor->Inner ring scaling factor->Differential coefficient of outer ring->Differential coefficient of inner ring->Integration coefficient of outer ring->Inner loop integral coefficient->And adjustment coefficient->。
In this embodiment, 7 coefficients need to be output, so 7 coefficient models are provided, each coefficient model outputs one coefficient, and the weight and the bias amount in each coefficient model are different.
First, theState quantity at sub-regulation->The formula of (2) is:
wherein,,is->Forgetfulness during secondary adjustment, +.>Is->Input during secondary adjustment, +.>Is->The state at the time of the secondary adjustment.
First, theForgetfulness during secondary adjustment +.>The formula of (2) is:
wherein,,to activate the function +.>Is->Forgetting weight at secondary adjustment, +.>Is->Forgetting bias at secondary adjustment +.>Is->Voltage target difference at secondary regulation, +.>Is->Output of coefficient model at sub-adjustment, +.>Is->Load current value at the time of secondary adjustment.
First, theInput at sub-setting ∈>The formula of (2) is:
wherein,,to activate the function +.>Is->First input weight at sub-adjustment, +.>Is->First input bias at sub-adjustment, +.>Is->Second input weight at secondary adjustment, +.>Is->Second input bias at secondary adjustment, +.>As hyperbolic tangent function, +.>Is->Voltage target difference at secondary regulation, +.>Is->Output of coefficient model at sub-adjustment, +.>Is->Load current value at the time of secondary adjustment.
The load condition of the direct current power supply can directly influence the output state and the system stability of the direct current power supply, and even directly relate to the equipment safety of the direct current power supply. In order to improve the compatibility of a direct current power supply to a load without being influenced by parasitic parameters of the load, the self-adaptive fuzzy control model has self-adaptive capacity for adapting to the working state of the load, flexible adjustment of stability and safety is carried out, the time domain characteristics of the voltage target difference value and the load current value are extracted from a coefficient model with time domain memory, forgetting and updating functions on the voltage target difference value and the load current value, and the time domain characteristics are calculated and then used for adjusting each coefficient of the self-adaptive fuzzy control model, so that the problems that the prior art is highly dependent on analysis of a zero pole and solidification design of an analog electronic circuit, poor in flexibility, easy to be influenced by parasitic parameters of the load, and difficult to carry out dynamic adjustment such as safety control according to the electrifying condition of the load are solved.
In summary, the invention utilizes the error of the output voltage and the current state of the load to carry out dynamic feedback adjustment on the direct current power supply on the basis of the high frequency digital pulse wave preliminary driving direct current power supply with the duty ratio being the theoretical duty ratio through the self-adaptive fuzzy control model, so that the direct current power supply can adapt to various loads and stably and safely output, and has the advantages of high flexibility, strong robustness and good safety.
The principles and embodiments of the present invention have been described in detail with reference to specific examples, which are provided to facilitate understanding of the method and core ideas of the present invention; meanwhile, as those skilled in the art will have variations in the specific embodiments and application scope in accordance with the ideas of the present invention, the present description should not be construed as limiting the present invention in view of the above.
Those of ordinary skill in the art will recognize that the embodiments described herein are for the purpose of aiding the reader in understanding the principles of the present invention and should be understood that the scope of the invention is not limited to such specific statements and embodiments. Those of ordinary skill in the art can make various other specific modifications and combinations from the teachings of the present disclosure without departing from the spirit thereof, and such modifications and combinations remain within the scope of the present disclosure.