PWM wave generation method, device and equipment for wireless power transmission system

Abstract

The present application relates to the technical field of high-voltage power extraction, and provides a PWM wave generation method, device and equipment for a wireless power transmission system. When the model of the wireless power transmission system is mismatched or the control effect of the controller based on the original phase shift angle generation parameters deteriorates, the control effect of the controller on the wireless power transmission system is optimized, including: based on the estimated delay obtained by identification, the system model including the estimated delay is phase-decomposed, and the minimum phase part obtained by the decomposition is combined with a first-order low-pass filter to obtain an internal model controller; the internal model controller is equivalently converted to obtain a unit negative feedback PID controller; the estimated delay term in the unit negative feedback PID controller is approximated by a first-order Taylor expansion to obtain an approximated unit negative feedback PID controller; the proportional and integral coefficients extracted from the approximated unit negative feedback PID controller in the form of PI are used as phase shift angle generation parameters to complete the redesign of the phase shift angle generation parameters.

Description

Technical Field

[0001] The present application relates to the field of high voltage power generation technology, and in particular to a PWM wave generation method, device and computer equipment for a wireless power transmission system. Background Art

[0002] With the continuous development and increasing complexity of power systems and transmission lines, it is particularly important to monitor the lines and important nodes in real time and accurately. Therefore, monitoring equipment such as sensors or smart gateways are increasingly used in high-voltage transmission lines. CT (current transformer) power take-off is widely used in the field of high-voltage transmission. It directly takes energy from the transmission line through the principle of electromagnetic induction to power the secondary side monitoring equipment. At the same time, it also ensures the insulation distance and meets the requirements of high-voltage transmission lines for electrical insulation. In addition, if the monitoring equipment is large in size and weight, the transmission line is not easy to bear, and a large tensile deformation will occur, which will also destroy the insulation of the transmission line to the ground. Therefore, the CT power take-off part can be hung on the transmission line, and the power-consuming equipment can be placed on the pole tower, and the ground insulation can be achieved with the help of insulators. At the same time, wireless power transmission is used to transmit the power taken from the CT power take-off part to the power-consuming equipment.

[0003] A controller that can achieve good output voltage control and power regulation is very important for wireless power transmission (WPT) systems. The controller generates a phase shift angle based on a phase shift angle generation parameter, and a PWM wave generator generates a corresponding PWM wave based on the phase shift angle generated by the controller, thereby realizing wireless transmission of electric energy in the wireless power transmission system.

[0004] Due to problems such as processing and manufacturing errors and the degree of coil alignment during installation, there will be a certain deviation between the actual wireless power transmission system and the preset system model. In addition, under normal circumstances, the monitoring equipment is required to work normally and independently for several years. During this process, device aging is also inevitable. Coupled with the influence of environmental factors, the degree of coil alignment will also shift, and the actual system model of the wireless power transmission system is bound to change. The phase shift angle generation parameters of the controller designed based on the original system model may also deteriorate the control effect of the controller, which requires the design of a new controller phase shift angle generation parameters based on the new system model. Summary of the invention

[0005] Based on this, in order to solve the above problems, the present application provides a PWM wave generation method, device, equipment, storage medium and computer program product for a wireless power transmission system.

[0006] A method for generating a PWM wave of a wireless power transmission system, the method comprising:

[0007] Obtaining an estimated time delay between an input and an output for a wireless power transfer system;

[0008] Acquire a system model including the estimated time delay; the system model including the estimated time delay is used to describe the relationship between the input and the output;

[0009] Decomposing the system model including the estimated time delay into a minimum phase part and a non-minimum phase part, and obtaining an internal model controller based on a combination of the minimum phase part and a first-order low-pass filter;

[0010] Performing an equivalent transformation on the internal model controller based on a system model including the estimated time delay to obtain a unit negative feedback PID controller;

[0011] Using a first-order Taylor expansion, the estimated time delay term in the unit negative feedback PID controller is approximated to obtain an approximated unit negative feedback PID controller;

[0012] The proportional and integral coefficients extracted from the approximated unit negative feedback PID controller in PI form are used as phase shift angle generation parameters;

[0013] A PWM wave of the wireless power transmission system is generated based on the phase shift angle obtained according to the phase shift angle generation parameter.

[0014] In one embodiment, the input is a phase shift angle and the output is a voltage;

[0015] The obtaining of an estimated time delay between an input and an output of the wireless power transmission system comprises:

[0016] Based on the optional value of the order and the optional value of the delay, a candidate system model set is obtained; each candidate system model in the candidate system model set is used to describe the relationship between the phase shift angle input to the wireless power transmission system and the voltage output by the wireless power transmission system;

[0017] Inputting a test phase shift angle sequence into the wireless power transmission system, and collecting a test voltage sequence output by the wireless power transmission system;

[0018] Based on the test phase shift angle sequence and the test voltage sequence, using Criteria, calculate the fitting ratio of each candidate system model;

[0019] Selecting a candidate system model whose fitting ratio is greater than a fitting ratio threshold from the candidate system model set;

[0020] Based on the AIC values ​​of the selected candidate system models, the candidate system model with the smallest AIC value among the selected candidate system models is used as the system model whose coefficients are to be estimated;

[0021] The optional value of the time delay in the system model where the coefficient is to be estimated is used as the estimated time delay of the system model.

[0022] In one embodiment, each candidate system model in the candidate system set is a system model of output error:

[0023]

[0024] Where s represents the Laplace operator; τ>0 represents the delay; θ=[a1,…,a n ,b0,…,b m ] T ; A(s,θ)=s n +a1s n-1 +…+a n ; B(s,θ)=b0s m +b1s m-1 +…+b m ; {e(t k )} is the output error sequence; {u(t k )} is the phase shift angle sequence input to the wireless power transmission system; {x(t k )} and {y(t k )} are respectively the sampled value and the real value of the voltage sequence output by the wireless power transmission system; the input phase shift angle sequence and the output voltage sequence are both at t k = kT (k∈N), where T is the sampling time; n and m are the order of the denominator and the order of the numerator of the system model respectively;

[0025] based on The fitting ratios and AIC values ​​obtained by the criteria are:

[0026] in,

[0027] in, Represents the difference between the sampled value and the true value of the voltage sequence output by the wireless power transmission system. yes The average value of y(k) represents the sampling value of the voltage sequence output by the wireless power transmission system. is the mean value of y(k); N is the number of groups of sampling data.

[0028] In one embodiment, the method further comprises:

[0029] Based on the optional values ​​of the delay and the optional values ​​of the order in the system model to be estimated, the coefficients are estimated by minimizing the output error, as shown in the following formula:

[0030]

[0031] In one embodiment, the system model including the estimated delay is G m (s) characterizes, the minimum phase part is G m- (s) and the non-minimum phase part is G m+ (s);

[0032] G m (s), G m- (s) and G m+ The relationship between (s) is: G m (s) = G m- (s)G m+ (s);

[0033] If G m (s) is a first-order model including the estimated delay, then:

[0034]

[0035] G m+ (s) = e -τs ; where τ is the time delay, and a and b are the estimated parameters of the first-order model.

[0036] In one embodiment, the internal model controller is represented by Q(s), and the first-order low-pass filter is represented by F(s), then:

[0037] Q(s)=G m- (s)F(s)

[0038]

[0039] Among them, r is set to 1; λ is the adjustable parameter of the first-order low-pass filter.

[0040] If the unit negative feedback PID controller uses G c Characterization, then the unit negative feedback PID controller obtained by equivalently transforming the internal model controller based on the system model including the estimated time delay is:

[0041]

[0042] In one embodiment, the time delay term in the unity negative feedback PID controller is e -τs , and e -τs The approximate first-order Taylor expansion is 1-τs;

[0043] The unit negative feedback PID controller obtained by approximating the time delay term using the first-order Taylor expansion is:

[0044]

[0045] In one embodiment, the proportional and integral coefficients extracted from the approximated unit negative feedback PID controller in PI form as phase shift angle generation parameters include:

[0046] Rewrite the approximated unit negative feedback PID controller into PI form and we get

[0047] Comparison and get as well as Among them, the K p and the T i Generates parameters for the phase shift angle.

[0048] A PWM wave generating device for a wireless power transmission system, the device comprising:

[0049] An estimated delay acquisition module, used to acquire an estimated delay between an input and an output of a wireless power transmission system;

[0050] A system model acquisition module, used to acquire a system model including the estimated time delay; the system model including the estimated time delay is used to describe the relationship between the input and the output;

[0051] An internal model controller acquisition module, used for decomposing the system model including the estimated time delay into a minimum phase part and a non-minimum phase part, and obtaining an internal model controller based on a combination of the minimum phase part and a first-order low-pass filter;

[0052] An equivalent conversion module, used for performing an equivalent conversion on the internal model controller based on a system model including the estimated time delay to obtain a unit negative feedback PID controller;

[0053] An approximation module is used to approximate the estimated time delay term in the unit negative feedback PID controller by using a first-order Taylor expansion to obtain an approximated unit negative feedback PID controller;

[0054] A phase shift angle generation parameter acquisition module is used to extract the proportional and integral coefficients from the approximated unit negative feedback PID controller in PI form as phase shift angle generation parameters;

[0055] The PWM wave generating module is used to generate the PWM wave of the wireless power transmission system based on the phase shift angle obtained according to the phase shift angle generating parameter.

[0056] A computer device comprises a memory and a processor, wherein the memory stores a computer program and the processor executes the above method.

[0057] A computer-readable storage medium stores a computer program, wherein the computer program is executed by a processor to execute the above method.

[0058] A computer program product stores a computer program, wherein the computer program is executed by a processor to execute the above method.

[0059] The PWM wave generation method, device, computer equipment, storage medium and computer program product of the wireless power transmission system are as follows: when the system model of the wireless power transmission system is mismatched or the control effect of the controller of the wireless power transmission system based on the original phase shift angle generation parameters deteriorates, based on the estimated time delay obtained by identification, the system model including the estimated time delay is phase decomposed, and the minimum phase part obtained by the decomposition is combined with a first-order low-pass filter to obtain an internal model controller; and the internal model controller is equivalently converted based on the system model including the estimated time delay to obtain a unit negative feedback PID controller; the estimated time delay term in the unit negative feedback PID controller is approximated by using a first-order Taylor expansion to obtain an approximated unit negative feedback PID controller; the proportional and integral coefficients extracted from the approximated unit negative feedback PID controller in PI form are used as phase shift angle generation parameters to complete the redesign of the phase shift angle generation parameters, and when the model of the wireless power transmission system is mismatched, the control effect of the controller on the wireless power transmission system is optimized. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 Modeling and control schematics for wireless power transfer systems applied to smart gateways;

[0061] Figure 2 This is the schematic diagram of the wireless power transmission system;

[0062] Figure 3 A schematic flow chart of a PWM wave generating method of a wireless power transmission system in one embodiment;

[0063] Figure 4 Design schematics for wireless power transfer system identification and controller parameters;

[0064] Figure 5 Design schematics for identifying delays and controller parameters in the host computer;

[0065] Figure 6 It is the time domain characteristic curve of the model under different sampling intervals of a WPT system;

[0066] Figure 7 The logarithmic frequency characteristic curve of the model under different sampling intervals of a WPT system;

[0067] Figure 8A structural block diagram of a PWM wave generating device of a wireless power transmission system in one embodiment;

[0068] Fig. 9 FIG. 4 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0069] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0070] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0071] In the present application, when the system model mismatch occurs or the control effect of the original controller deteriorates after the entire wireless power transmission system has been running for a period of time, the system delay identification of the wireless power transmission system is started, and the phase shift angle generation parameters of the new controller are designed according to the identified delay. The present application can send the input and output sampling data of the wireless power transmission system collected by the sensor to the host computer through the intelligent gateway, perform the system model delay identification and system model parameter identification on the host computer, and obtain a control-oriented system model; and design the new phase shift angle generation parameters of the controller based on the system model, and then the host computer feeds back the new phase shift angle generation parameters to the intelligent gateway to load the new phase shift angle generation parameters into the controller, so as to update the parameters of the controller and optimize the control effect of the controller on the system.

[0072] The present application can update the phase shift angle generation parameters of the controller of the wireless power transmission system applied to the intelligent gateway as required to optimize the control effect of the controller on the system when the system model is mismatched.

[0073] The solution provided in this application involves the modeling and controller parameter design of the wireless power transmission system, which can be divided into a CT power supply part, a wireless power transmission part, a system identification part (used to identify the time delay of the system model and the parameters of the system model), a controller parameter design part (used to involve phase shift angle generation parameters) and an intelligent gateway.

[0074] The solution provided in the present application mainly includes the following steps: transmitting the sampling data of the wireless power transmission part to the intelligent gateway through the wireless communication module, and sending the system sampling data to the host computer through the intelligent gateway; identifying the system model delay and parameters on the host computer to obtain a control-oriented system model; the controller parameter design part derives the phase shift angle generation parameters based on the system model; the updated phase shift angle generation parameters are sent to the wireless power transmission part and loaded into the controller to optimize the control effect of the controller on the wireless power transmission system when the system model is mismatched.

[0075] Furthermore, for the system identification part, the sampling interval does not strictly depend on the real time delay of the system. By matching the time delay and the parameters of the system model, a system model that can better describe the dynamic characteristics of the wireless power transmission system can be obtained when the parameters of the time delay and the system model are not accurately identified. Then, through the controller parameter design part, the controller parameter design that does not strictly depend on the accuracy of the time delay identification can be realized.

[0076] In general, the solution provided by this application includes the following main steps:

[0077] Step S1, the CT power supply part includes a magnetic core, a power supply coil, a protection circuit, a rectifier circuit, and a voltage stabilizing circuit, which is suspended on the high-voltage transmission line and is used to obtain electrical energy from the high-voltage transmission line; the wireless power transmission part transmits the electrical energy obtained by the CT power supply part to the intelligent gateway placed on the pole tower; the system identification part and the controller parameter design part are located in the host computer, which are used to perform system model delay and system model parameter identification on the wireless power transmission system, as well as new controller parameter design.

[0078] Step S2, when the wireless power transmission system runs for a certain period of time or detects that the control effect of the controller on the wireless power transmission system has deteriorated, the system identification and new controller parameter design are started. First, the wireless power transmission system is switched to an open-loop state, and a set of input sequences are superimposed when the wireless power transmission system is working normally. The sensors placed at the input and output ends of the wireless power transmission system collect their input and output data, and the collected data is packaged and sent to the intelligent gateway through the wireless communication module, and then the intelligent gateway sends the sampled data back to the host computer.

[0079] Step S3, in the upper computer, the system delay and system parameter identification of the wireless power transmission system are performed based on the collected data. Due to hardware limitations, there is usually a time delay in the wireless power transmission system, and ignoring the time delay will reduce the modeling accuracy of the wireless power transmission system and affect the performance of the controller. If the total delay is close to or even greater than the sampling period of the data, the controller design needs to consider the impact of the time delay on the model. Therefore, in addition to considering the order and various coefficients of the system model, a pure time delay part is added after the output error model to accurately describe the dynamic characteristics of the wireless power transmission system. Usually, the user first sets the order (usually set to a low-order model) and the optional range of the time delay to determine a set of models, and based on the auxiliary variable method, the method is used. The criterion calculates the fit ratio of each model, and sorts the models in the set according to this index (the fit ratio is between 0 and 1, and the closer the fit ratio is to 1, the higher the model ranking); select a model with the lowest AIC value (usually a large negative number) from the top ranked models, and the delay of this model is used as the estimated delay of the model for the subsequent controller design. After the model order and estimated delay are determined, the coefficients of the system model are estimated by minimizing the output error.

[0080] Step S4, use internal model control to obtain new wireless power transmission system controller parameters. Decompose the identified system model into the minimum phase part and the non-minimum phase part, and then introduce a first-order low-pass filter to obtain the final expression of the internal model controller, and then convert the controller into a unit negative feedback PID controller through equivalent transformation. Approximate the delay term of the unit negative feedback PID controller with a first-order Taylor expansion. For a first-order pure delay model, a PI-form controller can be obtained. The proportional and integral coefficients in the PI-form controller are the new controller parameters (i.e., the phase shift angle generation parameters).

[0081] Step S4 specifically includes: Figure 3 Steps shown:

[0082] Step S401, obtaining an estimated time delay between an input and an output of a wireless power transmission system;

[0083] Step S402, obtaining a system model including the estimated time delay; the system model including the estimated time delay is used to describe the relationship between the input and the output of the wireless power transmission system;

[0084] Step S403, decomposing the system model including the estimated time delay into a minimum phase part and a non-minimum phase part, and obtaining an internal model controller based on a combination of the minimum phase part and a first-order low-pass filter;

[0085] Step S404, performing an equivalent transformation on the internal model controller based on the system model including the estimated time delay to obtain a unit negative feedback PID controller;

[0086] Step S405, using a first-order Taylor expansion to approximate the estimated time delay term in the unit negative feedback PID controller to obtain an approximated unit negative feedback PID controller;

[0087] Step S406, using the proportional and integral coefficients extracted from the approximated unit negative feedback PID controller in PI form as phase shift angle generation parameters;

[0088] Step S407: generating a PWM wave of the wireless power transmission system based on the phase shift angle obtained according to the phase shift angle generation parameter.

[0089] In the above manner, when the system model of the wireless power transmission system is mismatched or the control effect of the controller of the wireless power transmission system based on the original phase shift angle generation parameters deteriorates, the system model including the estimated time delay is phase-decomposed based on the estimated time delay obtained by identification, and the minimum phase part obtained by the decomposition is combined with the first-order low-pass filter to obtain an internal model controller; and the internal model controller is equivalently converted based on the system model including the estimated time delay to obtain a unit negative feedback PID controller; the estimated time delay term in the unit negative feedback PID controller is approximated by using the first-order Taylor expansion to obtain an approximated unit negative feedback PID controller; the proportional and integral coefficients extracted from the approximated unit negative feedback PID controller in the form of PI are used as the phase shift angle generation parameters to complete the redesign of the phase shift angle generation parameters, and when the model of the wireless power transmission system is mismatched, the control effect of the controller on the wireless power transmission system is optimized; and the design process of the internal model controller is relatively simple, with few parameters, strong robustness and certain delay compensation capability.

[0090] Step S5, sending the new controller parameters to the intelligent gateway and loading them into the controller of the wireless power transmission system to achieve model adaptation and optimized control.

[0091] Step S6: The smart gateway usually has different working states. Under different working states, the system model of the wireless power transmission system will also be different. Therefore, for different working states, multiple sets of controller parameters can be designed according to the above steps.

[0092] The above steps S1 to S6 are described in detail below with reference to the accompanying drawings or formulas.

[0093] Step S1, establishing a wireless power transmission system based on CT power supply.

[0094] Figure 1The modeling and control schematic diagram of the wireless power transmission system applied to the intelligent gateway is shown. The wireless power transmission system is built based on the CT power supply part. The CT power supply part includes a magnetic core, a power supply coil, a protection circuit, a rectifier circuit, and a voltage stabilization circuit, which is suspended on the transmission line. The primary side of the transformer is a high-voltage transmission line, and its current is i1; the secondary coil is a power supply coil with a number of turns of n2, which can take energy from the high-voltage transmission line to supply power to the load; one end of the resonant capacitor C1 is connected to one end of the power supply coil to form a resonant circuit; the other end of the capacitor C1 is connected to one end of the transient suppression diode TVS, and the other end of the TVS is connected to the other end of the power supply coil. When a large current is generated by lightning strikes or high-voltage line faults, the excessive voltage generated by the power supply device will break through the TVS to form a loop to prevent the high voltage from damaging the subsequent circuit. The bridge rectifier consists of four diodes D1 to D4, which are used to rectify the AC current induced by the coil. The voltage stabilizing capacitor C2 is connected in parallel with the load and then connected to the output of the rectifier bridge, and then passes through the DC / DC voltage stabilizing module as the input of the wireless power transmission module.

[0095] like Figure 2 As shown in the figure, the wireless power transmission system with string-to-string compensation structure mainly consists of three stages. The first stage is the input stage. The full-bridge inverter composed of four thyristors (Q1, Q2, Q3, Q4) can convert the DC voltage U output by the DC / DC voltage regulator module into in Converted into a high-frequency square wave voltage. The PI-type controller outputs a control signal including a phase shift angle based on the voltage difference between the expected load voltage of the smart gateway and the actual load voltage of the smart gateway, as well as the phase shift angle generation parameters; the PWM generation module generates PWM waves (G1, G2, G3, G4) based on the phase shift angle in the control signal as control signals for the four thyristors. The second stage is a resonant coupling circuit composed of inductors L1 and L2. At the same time, capacitor C1, resistor R1 and L1 are connected in series, and capacitor C2, resistor R2 and L2 are connected in series, which plays the role of a resonant compensation and protection circuit. The third stage is a rectifier and filter circuit, which consists of four diodes D1 to D4, which are used to rectify the AC power transmitted to the secondary side and pass through a single capacitor C f After filtering, it is supplied to the intelligent gateway.

[0096] Assume that the smart gateway can be equivalent to a pure resistance load R o The main parameters of the WPT system relied on by this embodiment are shown in Table 1.

[0097] Table 1 Main parameters of the system

[0098]

[0099] Step S2, collecting input and output data of the WPT system.

[0100] When the WPT system runs for a certain period of time or detects that the control effect of the controller on the WPT system has deteriorated, the system identification (that is, the time delay of the system model and the parameters of the system model) and the design of new controller parameters are started. Figure 4 As shown in the figure, the WPT system is first switched to an open-loop state, and a phase shift angle M sequence is generated according to the preset shift pulse period Δ, register bit number n and amplitude α, and then superimposed on the system steady-state working phase shift angle The inverter phase shift angle sequence is collected as input data (the input data can be called the test phase shift angle sequence), and the voltage sensor placed at the output end of the wireless power transmission system collects output data (the output data can be called the test voltage sequence), and the collected data is packaged and sent to the intelligent gateway through the wireless communication device, and then the intelligent gateway sends the sampled data back to the host computer. Figure 5 As shown, system identification and controller parameter design are carried out in the host computer.

[0101] In this embodiment, the shift pulse period Δ of the M sequence is 5*sampling time, the number of register bits n is 4, and the amplitude α is 0.06π.

[0102] Step S3: system identification.

[0103] System identification mainly refers to identifying the time delay and parameters of the system model of the wireless power transmission system. The phase shift angle input to the wireless power transmission system can be used as input data, and the voltage output by the wireless power transmission system can be used as output data.

[0104] Among them, the wireless power transmission system can be described by the output error model, that is, each candidate system model in the above candidate system set is a system model of the output error:

[0105]

[0106] Where s represents the Laplace operator; τ>0 represents the delay; θ=[a1,…,a n ,b0,…,b m ] T ; A(s,θ)=s n +a1s n-1 +…+a n ; B(s,θ)=b0s m +b1s m-1 +…+b m ; {e(t k )} is the output error sequence; {u(t k )} is the phase shift angle sequence input to the wireless power transmission system; {x(t k )} and {y(t k)} are respectively the sampled value and the real value of the voltage sequence output by the wireless power transmission system; the input phase shift angle sequence and the output voltage sequence are both at t k = kT(k∈N), T is the sampling time; n and m are the order of the denominator and the order of the numerator of the system model respectively. Then according to the sampling data {y(t k )} and {u(t k )} Estimate the parameter vector θ and the time delay τ.

[0107] First, estimate the delay. The delay is composed of two indicators: and AIC to determine.

[0108] based on The fitting ratios and AIC values ​​obtained by the criteria are:

[0109] in,

[0110] in, Represents the difference between the sampled value and the true value of the voltage sequence output by the wireless power transmission system. yes The average value of y(k) represents the sampling value of the voltage sequence output by the wireless power transmission system. is the mean value of y(k); N is the number of groups of sampling data.

[0111] The user sets the order (usually a low-order model) and the optional range of the delay, for example, specifying min(τ)≤τ≤max(τ); n=1 or 2; m=1 or 2. The models in the candidate system model set are sorted according to the value of (the fitting ratio is between 0 and 1; the closer the fitting ratio is to 1, the higher the model ranking is); a model with the lowest AIC value (usually a large negative number) is selected from the top-ranked models, and the delay of this model is used as the estimated delay of the model for subsequent controller parameter design.

[0112] That is to say, the above step S401 specifically includes: obtaining a candidate system model set based on the optional value of the order and the optional value of the delay; each candidate system model in the candidate system model set is used to describe the relationship between the phase shift angle input to the wireless power transmission system and the voltage output by the wireless power transmission system; inputting a test phase shift angle sequence into the wireless power transmission system, collecting a test voltage sequence output by the wireless power transmission system; based on the test phase shift angle sequence and the test voltage sequence, using The invention discloses a method for realizing a method for realizing a system model of an automobile engine, wherein the method comprises the following steps: calculating a fitting ratio of each candidate system model; selecting a candidate system model whose fitting ratio is greater than a fitting ratio threshold from the set of candidate system models; taking a candidate system model whose AIC value is the smallest among the selected candidate system models based on the AIC values ​​of the selected candidate system models as the system model whose coefficient is to be estimated; and taking the optional value of the delay in the system model whose coefficient is to be estimated as the estimated delay of the system model.

[0113] After the order and delay of the system model are determined, the coefficients of the system model can be estimated by minimizing the output error through algorithms such as the least squares method. That is, the coefficients can be estimated by minimizing the output error based on the optional values ​​of the delay and the optional values ​​of the order in the system model to be estimated, as shown in the following formula:

[0114]

[0115] Through the above system identification method, the matching of system model delay and parameters under different sampling times can be achieved, so that the obtained system model can better describe the dynamic characteristics of the system.

[0116] like Figure 6 and Figure 7 As shown in the figure, for this WPT system, models with different time delays are obtained at different sampling time intervals, which have similar outputs in the time domain, and the logarithmic frequency characteristic curves are basically the same in the low frequency. Although there are differences in the estimated time delay and fitting ratio, the dynamic responses of the estimated models based on different sampling intervals are very similar, and they can all well reflect the dynamic characteristics of the system.

[0117] Among them, the system model including the above estimated delay can be used m (s) Characterization; For the WPT system shown in Table 1, when the sampling time is 1ms in the simulation model, the identified delay is 1ms, and the system model is:

[0118]

[0119] Step S4: controller parameter design.

[0120] The system model G obtained by the above steps is m (s) is decomposed into the minimum phase part G m- (s) and the non-minimum phase part G m+ (s), G m (s), G m- (s) and G m+ The relationship between (s) is: G m (s) = G m- (s)G m+ (s);

[0121] If G m (s) is a first-order model including the estimated delay, then:

[0122]

[0123] G m+ (s) = e -τs ;

[0124] where τ is the time delay, and a and b are the estimated parameters of the first-order model.

[0125] If the internal model controller is represented by Q(s) and the first-order low-pass filter is represented by F(s), then:

[0126] Q(s)=G m- (s)F(s)

[0127]

[0128] Among them, r is set to 1; λ is the adjustable parameter of the first-order low-pass filter. The smaller λ is, the faster the closed-loop response of the WPT system is; conversely, the closed-loop response is slower.

[0129] If the unit negative feedback PID controller uses G c Characterization, then the unit negative feedback PID controller obtained by equivalently transforming the internal model controller based on the system model including the estimated time delay is:

[0130]

[0131] In order to make the controller structure a PI structure, the delay term e in the unit negative feedback PID controller -τs Using the first-order Taylor expansion 1-τs approximation, we get e -τs ≈1-τs; that is, with e -τs The approximate first-order Taylor expansion is 1-τs.

[0132] The unit negative feedback PID controller obtained by approximating the time delay term using the first-order Taylor expansion is:

[0133]

[0134] Next, rewrite the approximated unit negative feedback PID controller into PI form and obtain

[0135] Then, compare and get as well as Among them, the K p and the T i Generates parameters for the phase shift angle.

[0136] For the system shown in Table 1, we can take b = -1617, a = 280.3, τ = 0.001, λ = 0.004, and substitute them to get K p =-1.237×10 -1 , T i =3.568×10 -3 .

[0137] Step S5, load controller parameters -

[0138] The new controller parameters (i.e. K p and T i ) is sent to the intelligent gateway and loaded into the controller of the wireless power transmission system to achieve model adaptation and optimization control.

[0139] Step S6: The smart gateway usually has different working states. In different working states, the wireless power transmission system model will also be different. Therefore, for different working states, multiple sets of controller parameters can be designed according to the above steps.

[0140] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0141] In one embodiment, Figure 8 As shown, a PWM wave generating device of a wireless power transmission system is provided, comprising:

[0142] An estimated delay acquisition module 801 is used to acquire an estimated delay between an input and an output of a wireless power transmission system;

[0143] A system model acquisition module 802 is used to acquire a system model including the estimated time delay; the system model including the estimated time delay is used to describe the relationship between the input and the output;

[0144] An internal model controller acquisition module 803, used to decompose the system model including the estimated time delay into a minimum phase part and a non-minimum phase part, and obtain an internal model controller based on a combination of the minimum phase part and a first-order low-pass filter;

[0145] An equivalent conversion module 804 is used to perform an equivalent conversion on the internal model controller based on the system model including the estimated time delay to obtain a unit negative feedback PID controller;

[0146] An approximation module 805 is used to approximate the estimated time delay term in the unit negative feedback PID controller by using a first-order Taylor expansion to obtain an approximated unit negative feedback PID controller;

[0147] A phase shift angle generation parameter acquisition module 806 is used to extract the proportional and integral coefficients from the approximated unit negative feedback PID controller in PI form as phase shift angle generation parameters;

[0148] The PWM wave generating module 807 is used to generate the PWM wave of the wireless power transmission system based on the phase shift angle obtained according to the phase shift angle generating parameter.

[0149] In one embodiment, the input is a phase shift angle and the output is a voltage;

[0150] The estimated delay acquisition module 801 is further used to obtain a candidate system model set based on the optional value of the order and the optional value of the delay; each candidate system model in the candidate system model set is used to describe the relationship between the phase shift angle input to the wireless power transmission system and the voltage output by the wireless power transmission system; input a test phase shift angle sequence to the wireless power transmission system, and collect a test voltage sequence output by the wireless power transmission system; based on the test phase shift angle sequence and the test voltage sequence, use The invention discloses a method for realizing a method for realizing a system model of an automobile engine, wherein the method comprises the following steps: calculating a fitting ratio of each candidate system model; selecting a candidate system model whose fitting ratio is greater than a fitting ratio threshold from the set of candidate system models; taking a candidate system model whose AIC value is the smallest among the selected candidate system models based on the AIC values ​​of the selected candidate system models as the system model whose coefficient is to be estimated; and taking the optional value of the delay in the system model whose coefficient is to be estimated as the estimated delay of the system model.

[0151] In one embodiment, each candidate system model in the candidate system set is a system model of output error:

[0152]

[0153] Where s represents the Laplace operator; τ>0 represents the delay; θ=[a1,…,a n ,b0,…,bm ] T ; A(s,θ)=s n +a1s n-1 +…+a n ; B(s,θ)=b0s m +b1s m-1 +…+b m ; {e(t k )} is the output error sequence; {u(t k )} is the phase shift angle sequence input to the wireless power transmission system; {x(t k )} and {y(t k )} are respectively the sampled value and the real value of the voltage sequence output by the wireless power transmission system; the input phase shift angle sequence and the output voltage sequence are both at t k = kT (k∈N), where T is the sampling time; n and m are the order of the denominator and the order of the numerator of the system model respectively;

[0154] based on The fitting ratios and AIC values ​​obtained by the criteria are:

[0155] in,

[0156] in, Represents the difference between the sampled value and the true value of the voltage sequence output by the wireless power transmission system. yes The average value of y(k) represents the sampling value of the voltage sequence output by the wireless power transmission system. is the mean value of y(k); N is the number of groups of sampling data.

[0157] In one embodiment, the apparatus further includes a coefficient estimation module, which is used to estimate each coefficient by minimizing the output error based on the optional delay value and the optional order value in the system model of the coefficient to be estimated, as shown in the following formula:

[0158]

[0159] In one embodiment, the system model including the estimated delay is G m (s) characterizes, the minimum phase part is G m- (s) and the non-minimum phase part is G m+ (s);

[0160] G m (s), G m- (s) and G m+ The relationship between (s) is: G m (s) = G m-(s)G m+ (s);

[0161] If G m (s) is a first-order model including the estimated delay, then:

[0162]

[0163] G m+ (s) = e -τs ; where τ is the time delay, and a and b are the estimated parameters of the first-order model.

[0164] In one embodiment, the internal model controller is represented by Q(s), and the first-order low-pass filter is represented by F(s), then:

[0165] Q(s)=G m- (s)F(s)

[0166]

[0167] Among them, r is set to 1; λ is the adjustable parameter of the first-order low-pass filter.

[0168] If the unit negative feedback PID controller uses G c Characterization, then the unit negative feedback PID controller obtained by equivalently transforming the internal model controller based on the system model including the estimated time delay is:

[0169]

[0170] In one embodiment, the time delay term in the unity negative feedback PID controller is e -τs , and e -τs The approximate first-order Taylor expansion is 1-τs;

[0171] The unit negative feedback PID controller obtained by approximating the time delay term using the first-order Taylor expansion is:

[0172]

[0173] In one embodiment, the phase shift angle generation parameter acquisition module is used to rewrite the approximated unit negative feedback PID controller into PI form to obtain

[0174] Comparison and get as well as Among them, the K p and the T i Generates parameters for the phase shift angle.

[0175] The specific definition of the PWM wave generating device of the wireless power transmission system can be found in the definition of the PWM wave generating method of the wireless power transmission system mentioned above, which will not be repeated here. Each module in the PWM wave generating device of the wireless power transmission system can be implemented in whole or in part by software, hardware and a combination thereof. Each of the above modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to each of the above modules.

[0176] In one embodiment, a computer device is provided, whose internal structure diagram can be as follows: Fig. 9 As shown. The computer device includes a processor, a memory and a network interface connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store PWM wave generation data of a wireless power transmission system. The network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a PWM wave generation method of a wireless power transmission system is implemented.

[0177] Those skilled in the art will understand that Fig. 9 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0178] In one embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps in the above-mentioned various method embodiments when executing the computer program.

[0179] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0180] In one embodiment, a computer program product is provided, on which a computer program is stored, and the computer program is used by a processor to execute the steps in the above-mentioned various method embodiments.

[0181] Those of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the above-mentioned computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory or optical memory, etc. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0182] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0183] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A PWM wave generation method for a wireless power transmission system, characterized in that: The method comprises: Obtaining an estimated time delay between an input and an output of a wireless power transfer system; the input is a phase shift angle, and the output is a voltage; the phase shift angle belongs to an inverter; Acquire a system model including the estimated time delay; the system model including the estimated time delay is used to describe the relationship between the input and the output; Decomposing the system model including the estimated time delay into a minimum phase part and a non-minimum phase part, and obtaining an internal model controller based on a combination of the minimum phase part and a first-order low-pass filter; Performing an equivalent transformation on the internal model controller based on a system model including the estimated time delay to obtain a unit negative feedback PID controller; Using a first-order Taylor expansion, the estimated time delay term in the unit negative feedback PID controller is approximated to obtain an approximated unit negative feedback PID controller; The proportional and integral coefficients extracted from the approximated unit negative feedback PID controller in PI form are used as phase shift angle generation parameters; generating a PWM wave of the wireless power transmission system based on a phase shift angle obtained according to the phase shift angle generation parameter; The system model including the estimated delay is G m (s) characterizes, the minimum phase part is G m- (s) and the non-minimum phase part is G m+ (s); G m (s), G m- (s) and G m+ The relationship between (s) is: G m (s) = G m- (s)G m+ (s); if G m (s) is a first-order model including the estimated delay, then: G m+ (s) = e -τs ; where τ is the time delay, and a and b are the estimated parameters of the first-order model.

2. The method according to claim 1, characterized in that The obtaining of an estimated time delay between an input and an output of the wireless power transmission system comprises: Based on the optional value of the order and the optional value of the delay, a candidate system model set is obtained; each candidate system model in the candidate system model set is used to describe the relationship between the phase shift angle input to the wireless power transmission system and the voltage output by the wireless power transmission system; Inputting a test phase shift angle sequence into the wireless power transmission system, and collecting a test voltage sequence output by the wireless power transmission system; Based on the test phase shift angle sequence and the test voltage sequence, using Criteria, calculate the fitting ratio of each candidate system model; Selecting a candidate system model whose fitting ratio is greater than a fitting ratio threshold from the candidate system model set; Based on the AIC values ​​of the selected candidate system models, the candidate system model with the smallest AIC value among the selected candidate system models is used as the system model whose coefficients are to be estimated; Using the optional value of the time delay in the system model whose coefficient is to be estimated as the estimated time delay of the system model; based on The fitting ratios and AIC values ​​obtained by the criteria are: in, in, Represents the difference between the sampled value and the true value of the voltage sequence output by the wireless power transmission system. yes The average value of y(k) represents the sampling value of the voltage sequence output by the wireless power transmission system. is the average value of y(k); N is the number of groups of sampling data; n and m are the order of the denominator and the order of the numerator of the system model respectively.

3. The method according to claim 2, characterized in that Each candidate system model in the candidate system set is a system model of output error: Where s represents the Laplace operator; τ>0 represents the delay; θ=[a1,…,a n ,b0,…,b m ] T ; A(s,θ)=s n +a1s n-1 +…+a n ; B(s,θ)=b0s m +b1s m-1 +…+b m ; {e(t k )} is the output error sequence; {u(t k )} is the phase shift angle sequence input to the wireless power transmission system; {x(t k )} and {y(t k )} are respectively the sampled value and the real value of the voltage sequence output by the wireless power transmission system; the input phase shift angle sequence and the output voltage sequence are both at t k = kT(k∈N), where T is the sampling time.

4. The method according to claim 3, characterized in that: The method further comprises: Based on the optional values ​​of the delay and the optional values ​​of the order in the system model to be estimated, the coefficients are estimated by minimizing the output error, as shown in the following formula:

5. The method according to claim 1, characterized in that The internal model controller is represented by Q(s), and the first-order low-pass filter is represented by F(s), then: Q(s)=G m- (s)F(s) Among them, r is set to 1; λ is the adjustable parameter of the first-order low-pass filter; If the unit negative feedback PID controller uses G c Characterization, then the unit negative feedback PID controller obtained by equivalently transforming the internal model controller based on the system model including the estimated time delay is:

6. The method according to claim 5, characterized in that The time delay term in the unity negative feedback PID controller is e -τs , and e -τs The approximate first-order Taylor expansion is 1-τs; The unit negative feedback PID controller obtained by approximating the time delay term using the first-order Taylor expansion is:

7. The method according to claim 6, characterized in that The proportional and integral coefficients extracted from the approximated unit negative feedback PID controller in PI form as phase shift angle generation parameters include: Rewrite the approximated unit negative feedback PID controller into PI form and we get Comparison and get as well as Among them, the K p and the T i Generates parameters for the phase shift angle.

8. A PWM wave generating device for a wireless power transmission system, characterized in that: The device comprises: An estimated delay acquisition module, used to acquire an estimated delay between an input and an output of a wireless power transmission system; the input is a phase shift angle, and the output is a voltage; the phase shift angle belongs to an inverter; A system model acquisition module, used to acquire a system model including the estimated time delay; the system model including the estimated time delay is used to describe the relationship between the input and the output; An internal model controller acquisition module, used for decomposing the system model including the estimated time delay into a minimum phase part and a non-minimum phase part, and obtaining an internal model controller based on a combination of the minimum phase part and a first-order low-pass filter; An equivalent conversion module, used for performing an equivalent conversion on the internal model controller based on a system model including the estimated time delay to obtain a unit negative feedback PID controller; An approximation module is used to approximate the estimated time delay term in the unit negative feedback PID controller by using a first-order Taylor expansion to obtain an approximated unit negative feedback PID controller; A phase shift angle generation parameter acquisition module is used to extract the proportional and integral coefficients from the approximated unit negative feedback PID controller in PI form as phase shift angle generation parameters; A PWM wave generating module, used for generating a PWM wave of the wireless power transmission system based on a phase shift angle obtained according to the phase shift angle generating parameter; The system model including the estimated delay is G m (s) characterizes, the minimum phase part is G m- (s) and the non-minimum phase part is G m+ (s); G m (s), G m- (s) and G m+ The relationship between (s) is: G m (s) = G m- (s)G m+ (s); if G m (s) is a first-order model including the estimated delay, then: G m+ (s) = e -τs ; where τ is the time delay, and a and b are the estimated parameters of the first-order model.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the method according to any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

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