Segmented affine modeling method for MCR-BWPT system

Abstract

The invention provides an MCR-BWPT system segmented affine modeling method. The MCR-BWPT system segmented affine modeling method comprises the steps that the working mode of a system is determined according to the state change of each switching device in system operation; establishing a differential equation of the MCR-BWPT system; introducing a switching function to represent the switching state of an MCR-BWPT system inverter; writing an input power supply as a function represented by a switching function, and substituting the function represented by the switching function as an input variable into a differential equation of the MCR-BWPT system to obtain a continuous time state-space equation of the MCR-BWPT system; dividing an open period into v sub-periods; dividing the switching state of the switching tube in one sub-period; a v-step discrete method is adopted, and a state updating function in a sub-period is obtained; and obtaining a segmented affine model of the MCR-BWPT system based on the continuous time state-space equation and the state updating function of the MCR-BWPT system. And the purpose of establishing the accurate model of the MCR-BWPT system is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of wireless charging of electric vehicles, and in particular relates to a piecewise affine modeling method of an MCR-BWPT system. Background Art

[0002] "Promoting green and low-carbon economic and social development is a key link in achieving high-quality development. The promotion and application of electric vehicles provides strong support for achieving the "dual carbon" goals. With the support of policies and markets, China's new energy vehicles performed strongly in 2023, with annual production and sales exceeding 9 million vehicles, continuing the momentum of strong production and sales. my country's new energy vehicle production and sales have ranked first in the world for nine consecutive years, becoming an important force in promoting the transformation of the global automotive industry. With the rapid development of electric vehicles in my country, two-way wireless power transmission technology has become an effective way to solve the charging restrictions of electric vehicles and achieve the dual carbon goals.

[0003] MCR-BWPT technology enables bidirectional energy flow between electric vehicles and the power grid, which not only improves the convenience of charging, but also effectively reduces the load impact of a large number of electric vehicles on the distribution network. The MCR-BWPT system is composed of multiple switching devices. The on and off of the switching devices are regarded as discrete events. The occurrence of different discrete events makes the MCR-BWPT system in different working modes, and the MCR-BWPT system in different working modes is a subsystem described by continuous state variables. Within a cycle, the MCR-BWPT system switches orderly between different subsystems, so the MCR-BWPT system has switching characteristics and strong nonlinearity. How to establish a mathematical model that can describe the interaction between discrete events and continuous state variables and unify them, so as to accurately reflect the essence of the hybrid characteristics of the MCR-BWPT system, is the key to the modeling of the MCR-BWPT system. Traditional modeling and analysis methods of MCR-BWPT systems either ignore the switching action of the system and perform approximate linearization processing, simplifying the MCR-BWPT system, a typical nonlinear system, into a linear system, or ignore the periodic time-varying switching characteristics and segmented characteristics of the MCR-BWPT system, and cannot obtain an accurate model of the MCR-BWPT system. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a piecewise affine modeling method for an MCR-BWPT system, which at least partially solves the problem in the prior art that an accurate model of the MCR-BWPT system cannot be obtained.

[0005] The embodiment of the present invention provides a piecewise affine modeling method for an MCR-BWPT system, comprising:

[0006] Analyze the working characteristics and operation process of the MCR-BWPT system, determine the power transmission mode of the MCR-BWPT system, and determine the working mode of the system according to the state changes of each switch device during system operation;

[0007] The independent inductor current and independent capacitor voltage in the MCR-BWPT system are selected as continuous state variables, and the differential equation of the MCR-BWPT system is established;

[0008] The switching function is introduced to represent the switching state of the switch tube in each working mode of the MCR-BWPT system inverter;

[0009] Substituting the input power as a function represented by the switching function into the differential equation of the MCR-BWPT system, the continuous-time state space equation of the MCR-BWPT system is obtained;

[0010] Divide an open cycle into v sub-cycles;

[0011] Divide the switching state of the switch tube within a sub-cycle;

[0012] The v-step discretization method is used to obtain the state update function within a sub-period;

[0013] Based on the continuous-time state-space equations and state update function of the MCR-BWPT system, a piecewise affine model of the MCR-BWPT system is derived.

[0014] Optionally, analyzing the operating characteristics and operation process of the MCR-BWPT system, determining the power transmission mode of the MCR-BWPT system, and determining the operating mode of the system according to the state changes of each switching device during the operation of the system, includes:

[0015] The system characteristics and operation process of the MCR-BWPT system are analyzed, the forward or reverse power transmission mode of the MCR-BWPT system is determined, and the four working modes of the system are determined according to the state changes of each switching device during system operation.

[0016] Optionally, an on-cycle is divided into v sub-cycles, where v=4.

[0017] Optionally, the MCR-BWPT system includes a switch tube S1 and a switch tube S5, and the continuous-time state-space equation of the MCR-BWPT system includes a parameter u1 and a parameter u2.

[0018] Optionally, when the switch tube S1 is turned on, u1=1, and when it is turned off, u1=0; when the switch tube S5 is turned on, u2=1, and when it is turned off, u2=0.

[0019] Optionally, dividing an on-cycle into v sub-cycles includes:

[0020] Introduce 2v binary variables to represent the switching tube S1 and the switching tube S5 in kT s +mτ switch position at time T s is the switching period, m={0,1,…,v-1}, v∈N and v>1, τ is the sub-period, τ=T s / v.

[0021] Optionally, in a sub-cycle, the switch tube S1 and the switch tube S5 are in the following three switching states: the switch tube is always on, the switch tube is always off, and the switch tube is in a transition state between on and off.

[0022] Optionally, the state update function within a sub-period is derived, including

[0023] According to the different switching states of the switch tube S1 and the switch tube S5, different switching state combinations of the switch tubes may appear in the same sub-period, and the state update function of the subsystem in one sub-period is obtained based on the switching state combination.

[0024] Optionally, the piecewise affine model of the MCR-BWPT system is derived based on the continuous-time state space equation and the state update function of the MCR-BWPT system, including:

[0025] Based on the continuous-time state space equation and state update function of the MCR-BWPT system, the corresponding expression between the state variables and the duty cycle of the MCR-BWPT system is obtained;

[0026] Based on the corresponding expressions between state variables and duty cycle, the piecewise affine model of the MCR-BWPT system is derived.

[0027] The MCR-BWPT system piecewise affine modeling method provided by the present invention, through the MCR-BWPT system piecewise affine modeling method based on the v-step discretization method, has the advantages of being able to significantly reduce the period required for state space averaging, high calculation and derivation accuracy, high efficiency in establishing the PWA model and high accuracy of the obtained PWA model compared to traditional methods, thereby achieving the purpose of establishing an accurate model of the MCR-BWPT system. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0029] Figure 1 A flow chart of the piecewise affine modeling method for the MCR-BWPT system provided by the present invention;

[0030] Figure 2 This is the topological structure diagram of the MCR-BWPT system provided by the present invention;

[0031] Figure 3 The working waveform diagram of the switch signal of the MCR-BWPT system and the primary and secondary side series resonant inductor currents provided by the present invention;

[0032] Figure 4 The switch states of the switch tubes S1 and S5 in one cycle of the MCR-BWPT system provided by the present invention;

[0033] Figure 5 A comparison diagram of the PWA model of the MCR-BWPT system in the forward power transmission mode provided by the present invention, the nonlinear simulation model, and the primary and secondary resonant current waveform simulation of the traditional impedance model;

[0034] Figure 6 This is a comparison diagram of the primary and secondary side resonant current waveform simulations of the MCR-BWPT system PWA model and the nonlinear simulation model and the traditional impedance model under the reverse power transmission mode provided by the present invention. DETAILED DESCRIPTION

[0035] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0036] It should be clear that the following embodiments of the present invention are described by specific specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present invention.

[0037] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. It should be understood by those skilled in the art based on the invention that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0038] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention. The illustrations only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0039] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects described may be practiced without these specific details.

[0040] like Figure 1 As shown, a piecewise affine modeling method of an MCR-BWPT system based on a v-step discretization method comprises the following steps:

[0041] Step S1, firstly analyze the system characteristics and operation process of the MCR-BWPT system, determine the forward or reverse power transmission mode of the MCR-BWPT system, and determine the four working modes of the system according to the state changes of each switching device during the operation of the system;

[0042] like Figure 2 and Figure 3 As shown in the figure, U1 and U2 are the primary and secondary DC voltage sources respectively; the four MOSFET switches S1-S4 constitute the primary side H bridge; the four MOSFETs S5-S8 constitute the secondary side H bridge; the diodes D1-D8 are anti-parallel connected to the eight MOSFETs S1-S8 respectively; P 、u S are the output voltages of the primary and secondary side H bridges respectively; u Cp1 、u Cp2 are the primary and secondary side resonant compensation capacitor voltages respectively; i Lf1 、i Lf2 are the primary and secondary side series resonant compensation inductor currents respectively; i Lp 、i Ls are primary and secondary mutual inductance currents respectively; Lf1 , L f2 They are the primary and secondary side series compensation inductors; C P , C S They are the primary and secondary side parallel compensation capacitors; L P , L S are the primary and secondary self-inductances respectively; M is the mutual inductance of the coupling coil; L f1 , C P and L P It constitutes the LCL resonant compensation network at the transmitting end; L f2 , C S and L S It constitutes the LCL resonant compensation network at the receiving end; R1 and R2 are the internal resistance of the primary and secondary coils respectively; R P , R S are the equivalent resistances of the primary and secondary side compensation networks respectively.

[0043] Taking the forward power transmission mode as an example, the forward power transmission mode of the MCR-BWPT system is divided into four working modes in one switching cycle according to the different working states of the switch tube.

[0044] Mode 1: When t∈(t0,t1), the primary side series compensation inductor current i Lf1 It flows in the negative direction and decreases in the reverse direction to 0 at time t1, flowing through diodes D1 and D4 which are anti-parallel connected with MOS tube S1 and MOS tube S4; the secondary side series compensation inductor current i Lf2 The current flows in the positive direction and decreases to 0 at time t2, flowing through MOS tube S6 and MOS tube S7. After time t1, MOS tube S1 and MOS tube S4 are turned on, compensating the inductor current i Lf1 Starts to increase positively; in the stage t∈(t2,t3), the compensation inductor current i Lf2 After decreasing to 0 at time t2, it starts to flow in the negative direction, flows through diodes D6 and D7, and increases in the reverse direction.

[0045] Mode 2: At time t3, the MOS tubes S5 and S8 are given a turn-on signal, and the MOS tubes S6 and S7 are given a turn-off signal. At this time, the compensation inductor current i Lf1 The direction is positive, flowing through MOS tube S1 and MOS tube S4, and the positive direction decreases; during this stage, i Lf2 The direction is negative, flowing through diodes D6 and D7, and showing a trend of first decreasing in the reverse direction and then increasing.

[0046] Mode 3: MOS tube S2 and MOS tube S3 are turned on at time t4, while MOS tube S1 and MOS tube S4 are turned off. At this time, the compensation inductor current i Lf1The direction is positive, so at this time, the diode D2 and the diode D3 connected in anti-parallel with the MOS tube S2 and MOS tube S3 are used for freewheeling to compensate the inductor current i Lf1 The positive direction decreases to 0 at time t5; the switching state of the secondary side switch tube is consistent with the working mode q2, and flows through MOS tube S5 and MOS tube S8, showing a trend of first increasing in the reverse direction and then decreasing. Lf1 At time t5, it decreases to 0, flows through MOS tube S2 and MOS tube S3, and begins to increase in the reverse direction; while the compensation inductor current i Lf2 At time t6, the reverse direction decreases to 0, and then flows in the forward direction and flows through diodes D5 and D8.

[0047] Mode 4: MOS tube S6 and MOS tube S7 are turned on at time t7, while MOS tube S5 and MOS tube S8 are turned off. At this time, the switching state of the primary side switch tube is the same as that of the working mode q3; and the compensation inductor current i Lf2 The direction is positive, and it flows through MOS transistor S6 and MOS transistor S7, showing a trend of first decreasing and then increasing.

[0048] Step S2, establish the state space equations of the four working modes according to the continuous state variables and discrete state variables in the MCR-BWPT system; select the current of the independent inductor and the voltage of the independent capacitor in the MCR-BWPT system as the continuous state variables of the system as x(t)=[i Lf1 ,u Cp ,i Lp ,i Ls ,u Cs ,i Lf2 ] T , write the differential equation:

[0049] ,

[0050] The switch verification function h is introduced for the four switching states of the primary and secondary inverters of the MCR-BWPT system. 11 、h 12 、h 21 and h 22 :

[0051] ,

[0052] where h 11 With h 12 Complementary, h 21 With h 22 Complementary, follow:

[0053] ,

[0054] And h 11 +h22 =1, then:

[0055] ,

[0056] The differential equations of the primary and secondary series resonant inductor currents are obtained as follows:

[0057] ,

[0058] Therefore, the continuous-time state space equation of the MCR-BWPT system is established:

[0059] ,

[0060] The expression of the state space equation coefficient matrix A is:

[0061] ,

[0062] The expressions of the state space equation input matrices B1 and B2 are:

[0063] ,

[0064] The expression of the state space equation output matrix f is:

[0065] ,

[0066] The expression of the state space equation output matrix C is:

[0067] .

[0068] When the switch tube S1 is turned on, u1=1, and when it is turned off, u1=0; when the switch tube S5 is turned on, u2=1, and when it is turned off, u2=0.

[0069] Step S3, introducing a switching function to represent the switching states of the primary and secondary side inverters of the MCR-BWPT system;

[0070] Step S4, substituting the switch function as an input variable into the differential equation of the MCR-BWPT system to obtain the continuous time state space equation of the MCR-BWPT system;

[0071] S5, dividing an open period into v sub-periods;

[0072] S6, dividing the switch state of the switch tube in a sub-cycle;

[0073] S7, using the v-step discretization method (v=4), and deriving the state update function within a sub-period;

[0074] like Figure 5As shown, the v-step discretization method is used to divide a switching cycle of the MCR-BWPT system into v sub-cycles, and the state update function of the subsystem within a sub-cycle is obtained, which specifically includes the following steps:

[0075] Step a: Introduce 2v binary variables

[0076] The discrete sampling period is the switching period of the MCR-BWPT system, and the switching period is recorded as T s , which is divided into v sub-periods, each sub-period is τ=T s / v, v∈N and v>1. Use ξ n (m) to represent kT s The value of the state variable of subsystem n at time +mτ, m={0,1,…,v-1}, let ξ n (0)=x n (k),ξ n (v)=x n (k+1), so 2v binary variables are introduced to represent the switch tube S1 and the switch tube S5 at kT s +mτ time switch position, True means the switch is turned on:

[0077] ,

[0078] Step b: Write the state update function of the MCR-BWPT system within a sub-cycle according to the switch state

[0079] In a sub-cycle, the switch tube S1 and the switch tube S5 are in the following three switching states: The switch tube is always on; The switch tube is always disconnected; The switch tube is in a transition state between on and off. Depending on the different switch states of switch tubes S1 and S5, different switch state combinations may appear in the same sub-cycle, and the state update function of subsystem n in a sub-cycle can be obtained:

[0080] ,

[0081] In the formula, Φ n =e Aτ , ψ n1 =−A(I6−e Aτ )B1,ψ n2 =−A(I6−e Aτ )B2,f n =−A(I6−e Aτ )f.

[0082] When the switch tube S1 or the switch tube S5 works in the switch state ③, the ψn1(ave) =ψ n1 (vd1(k)−m) or ψ n2(ave) =ψ n1 (vd2(k)−m), because the values ​​of vd1(k)−m and vd2(k)−m are both greater than 0 and less than 1, the switching state ③ can be regarded as the weighted average of the switching state ① and the switching state ②.

[0083] Step S8: Obtaining the corresponding expression between the state variable and the duty cycle of the MCR-BWPT system, that is, the PWA model of the MCR-BWPT system, specifically includes the following steps:

[0084] The switching period of the MCR-BWPT system is divided into four equal parts, that is, v = 4 (τ = T s / 4), and then the corresponding expression between the state variables and duty cycle of the MCR-BWPT system is obtained:

[0085] ,

[0086] In the formula,

[0087] ,

[0088] ,

[0089] The simulation results of the modeling method proposed in the present invention, the traditional impedance modeling method and the nonlinear time domain simulation model under the forward and reverse power transmission modes are compared. Figure 5 and Figure 6 It can be seen that the traditional impedance model has large errors when the system resonant current runs to the peak and trough, while the PWA model can accurately describe the steady-state characteristics of the MCR-BWPT system with high accuracy.

[0090] By analyzing the working characteristics and operation process of the MCR-BWPT system, the forward and reverse power transmission modes of the MCR-BWPT system are given. The four working modes of the system are determined according to the state changes of each switch device during the operation of the system, and the differential equations are written in parallel. On this basis, the switch check function is introduced to represent the four switch states of the MCR-BWPT system, and the continuous time state space equation of the MCR-BWPT system is obtained. Based on this, one cycle of the MCR-BWPT system is divided into v sub-cycles, and the state update function within a sub-cycle is obtained. Finally, the PWA model of the MCR-BWPT system is obtained according to the state update function. By applying the v-step modeling method to the establishment of the PWA model of the MCR-BWPT system, the cycle required for the state space average can be significantly reduced, making the result more accurate. Therefore, as long as v is large enough, the constructed model will be closer to the real situation, thereby making the future state predicted by the state space method more accurate and reliable.

[0091] The basic principle of the present invention is described above in conjunction with specific embodiments. However, it should be pointed out that the advantages, strengths, effects, etc. mentioned in the present invention are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. must be possessed by each embodiment of the present invention. In addition, the specific details disclosed above are only for the purpose of illustration and facilitation of understanding, rather than limitation, and the above details do not limit the present invention to being implemented by adopting the above specific details.

[0092] In the present invention, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Words such as "including", "comprising", "having", etc. are open words, meaning "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used herein refer to the words "and / or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The word "such as" used herein refers to the phrase "such as but not limited to", and can be used interchangeably with it.

[0093] Additionally, as used herein, "or" used in a list of items beginning with "at least one" indicates a separate list, so that, for example, a list of "at least one of A, B, or C" means A or B or C, or AB or AC or BC, or ABC (i.e., A and B and C). Furthermore, the word "exemplary" does not mean that the example described is preferred or better than other examples.

[0094] It should also be noted that in the system and method of the present invention, each component or each step can be decomposed and / or recombined. Such decomposition and / or recombination should be regarded as equivalent solutions of the present invention.

[0095] Various changes, substitutions, and modifications of the techniques described herein may be made without departing from the teachings defined by the appended claims. Furthermore, the scope of the claims of the present invention is not limited to the specific aspects of the processes, machines, manufactures, compositions of events, means, methods, and actions described above. Currently existing or later to be developed processes, machines, manufactures, compositions of events, means, methods, or actions that perform substantially the same functions or achieve substantially the same results as the corresponding aspects described herein may be utilized. Thus, the appended claims include such processes, machines, manufactures, compositions of events, means, methods, or actions within their scope.

[0096] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present invention. Therefore, the present invention is not intended to be limited to the aspects shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

[0097] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present invention to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A piecewise affine modeling method for an MCR-BWPT system, characterized in that: include: Analyze the working characteristics and operation process of the MCR-BWPT system, determine the power transmission mode of the MCR-BWPT system, and determine the working mode of the system according to the state changes of each switch device during system operation; The independent inductor current and independent capacitor voltage in the MCR-BWPT system are selected as continuous state variables, and the differential equation of the MCR-BWPT system is established; The switching function is introduced to represent the switching state of the switch tube in each working mode of the MCR-BWPT system inverter; Write the input power as a function represented by the switching function and substitute it into the differential equation of the MCR-BWPT system to obtain the continuous time state space equation of the MCR-BWPT system; Divide an on cycle into v sub-periods; Divide the switching state of the switch tube within a sub-cycle; use v Step discretization method is used to obtain the state update function within a sub-period; Based on the continuous-time state-space equations and state update function of the MCR-BWPT system, a piecewise affine model of the MCR-BWPT system is derived.

2. The MCR-BWPT system segmented affine modeling method according to claim 1, characterized in that: The analysis of the working characteristics and operation process of the MCR-BWPT system, determining the power transmission mode of the MCR-BWPT system, and determining the working mode of the system according to the state changes of each switching device during the operation of the system include: The system characteristics and operation process of the MCR-BWPT system are analyzed to determine the forward or reverse power transmission mode of the MCR-BWPT system, and the four working modes of the system are determined according to the state changes of each switching device during system operation.

3. The MCR-BWPT system segmented affine modeling method according to claim 1, characterized in that: Divide an on cycle into v In each sub-cycle, v =4.

4. The MCR-BWPT system piecewise affine modeling method according to claim 1, characterized in that: The MCR-BWPT system uses the independent inductor current and the independent capacitor voltage of the system as state variables, establishes a system continuous state space equation, and links the switch states of the switch tube S1 and the switch tube S5 with the system input variables.

5. The MCR-BWPT system piecewise affine modeling method according to claim 4, characterized in that: When the switch S1 is turned on u 1=1, when disconnected u 1=0; when the switch tube S5 is turned on u 2=1, when disconnected u 2=0.

6. The MCR-BWPT system piecewise affine modeling method according to claim 5, characterized in that: The on cycle is divided into v sub-periods, including: Introduction 2 v A binary variable is used to represent the switching tube S1 and the switching tube S5. kT s + mτ The switch position at the moment, where T s is the switching cycle, m= {0,1,…, v -1}, v ∈N and v >1, τ is the sub-period, τ = T s / v。 7. The MCR-BWPT system piecewise affine modeling method according to claim 6, characterized in that: In a sub-cycle, the switch tube S1 and the switch tube S5 are in the following three switching states: the switch tube is always on, the switch tube is always off, and the switch tube is in a transition state between on and off.

8. The MCR-BWPT system piecewise affine modeling method according to claim 7, characterized in that: The step of obtaining a state update function within a sub-period includes: According to the different switching states of the switch tube S1 and the switch tube S5, different switching state combinations of the switch tubes may appear in the same sub-period, and the state update function of the subsystem in one sub-period is obtained based on the switching state combination.

9. The MCR-BWPT system piecewise affine modeling method according to claim 8, characterized in that: The MCR-BWPT system piecewise affine model is obtained based on the continuous-time state space equation and state update function of the MCR-BWPT system, including: Based on the continuous-time state space equation and state update function of the MCR-BWPT system, the corresponding expression between the state variables and the duty cycle of the MCR-BWPT system is obtained; Based on the corresponding expressions between state variables and duty cycle, the piecewise affine model of the MCR-BWPT system is derived.

Images