Full-mode energy control system and method of dual-time-scale cascade system

Abstract

The invention provides a full-mode energy control system of a dual-time-scale cascade system. The full-mode energy control system comprises a dual-time-scale cascade IPT-FSBB system and a control circuit, the control circuit comprises a voltage regulator, a current regulator, a proportional element, a PWM generator and a composite control unit. The input end of the current regulator is connected with the fast time scale structure IPT, the input end of the voltage regulator is connected with the slow time scale structure FABB, and the sampling value of the fast time scale structure IPT is connected with the input end of the composite control unit through the proportional element; the output end of the current regulator and the output end of the voltage regulator are connected with the composite control unit, the input end of the PWM generator is connected with the output end of the composite control unit, and the PWM generator is used for controlling the dual-time-scale cascade IPT-FSBB system. According to the invention, the port energy of the dual-time-scale cascade system is selected as a control target through the control circuit, so that the dynamic response of the dual-time-scale system is accurately tracked, and the calculation burden of a control algorithm and the hardware design cost are reduced.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to a full-modal energy control system and method for a dual-time-scale cascade system. Background Art

[0002] Inductive wireless charging (IPT) technology, as an alternative to traditional wired charging methods, has been widely used in underwater autonomous vehicles, drones, electric vehicles and other fields.

[0003] Electrolytic capacitors are commonly used as a decoupling method in cascaded systems. However, their lifespan is typically limited to a few thousand hours. In high-power systems, rising ambient temperatures further reduce the lifespan of electrolytic capacitors, causing their actual capacitance to deviate from the rated value. As the decoupling capacitor's capacitance decreases, maintaining a stable bus voltage becomes a challenge, which also means increased bus voltage ripple. Furthermore, the resonant frequency of the IPT system and the operating frequency of the subsequent FSBB converter are typically different, resulting in two timescale variations in the cascaded IPT-FSBB system.

[0004] Chinese patent application number CN 112068431 A discloses a dual-time-scale control method, system, device, and storage medium. The method includes the following steps: obtaining control variables and constructing a dual-time-scale model based on the control variables; determining a quasi-integral variable based on the control variables, and determining a steady-state target value for the controlled variable based on the dual-time-scale model; tracking the steady-state target value through dynamic control to obtain a set value for the underlying control, performing real-time control based on the set value, and obtaining the actual value of the real-time control; performing error compensation on the predicted value of the dynamic control based on the actual value, and performing control optimization based on the error-compensated predicted value. However, this technical solution is highly dependent on the dual-time-scale model and suffers from low real-time performance and steady-state accuracy.

[0005] Traditional single-timescale models, such as the generalized state-space average model, achieve precise control of port energy and rapid response to load switching. However, for dual-timescale cascade systems, no research has yet proposed energy models and control strategies for multiple timescale variables. Furthermore, traditional models and control strategies cannot be simply applied and require redesign. Summary of the Invention

[0006] In view of the defects in the prior art, the purpose of this application is to provide a full-modal energy control system and method for a dual-time-scale cascade system.

[0007] In one aspect of the present application, a full-modal energy control system of a dual-time-scale cascade system is provided, comprising: a dual-time-scale cascade IPT-FSBB system and a control circuit;

[0008] The dual-time-scale cascade IPT-FSBB system includes a fast-time-scale structure IPT and a slow-time-scale structure FSBB;

[0009] The control circuit includes: a voltage regulator, a current regulator, a proportional link, a PWM generator and a composite control unit;

[0010] The input end of the current regulator is connected to the fast time scale structure IPT, the input end of the voltage regulator is connected to the slow time scale structure FABB, and the sampling value of the fast time scale structure IPT is connected to the input end of the composite control unit via the proportional link;

[0011] The output ends of the current regulator and the voltage regulator are connected to the composite control unit, and the input end of the PWM generator is connected to the output end of the composite control unit, for controlling the dual-time-scale cascaded IPT-FSBB system through the PWM generator.

[0012] Furthermore, the fast time scale structure includes an LCC-LCC resonant compensation network, wherein the primary side of the LCC-LCC compensation network is provided with a capacitor C1 and a capacitor C p , the capacitor C1 and the capacitor C p The sampling value is passed through the proportional link K C1 and K Cp ;

[0013] The slow time scale structure includes a bus capacitor C bus and power inductor L;

[0014] The current sampling value iL of the power inductor L is adjusted by the current regulator and then input into the composite control unit; the bus capacitor C bus The bus voltage sampling value U Cbus After being regulated by the voltage regulator, it is input into the composite control unit;

[0015] An energy control module is provided in the composite control unit for realizing full-modal energy control through a cascade system energy control strategy.

[0016] Furthermore, the minimum current required for zero voltage switching ZVS operation is -I L_ZVS =-2C oss U Cbus / t d Among them, C oss is the output capacitance, t d is the dead time;

[0017] The current sampling value iL and the minimum current -I L_ZVSThe difference after comparison is input into the current regulator, and the output result of the current regulator is the first input variable of the energy control module, which is used to output the conduction duty cycle of the subsequent converter of the slow time scale structure required by the energy control strategy of the cascade system in the next cycle;

[0018] The bus voltage sampling value U Cbus With reference value U Cbus_ref The difference after comparison is input into the voltage regulator, and the output result of the voltage regulator is used as the second input variable of the energy control module to calculate the subsequent input energy of the energy control strategy port of the cascade system;

[0019] The sampling values of the capacitor C1 and the capacitor Cp are output through the proportional links KC1 and KCp as the third input variable and the fourth input variable of the full-modal energy control, which are used to calculate the input energy in the energy control strategy of the cascade system.

[0020] Furthermore, the fast time scale structure further includes a primary inverter, primary-secondary coupling coils L1 and L2, and a secondary active rectifier;

[0021] The first output terminal and the second output terminal of the primary inverter are respectively connected to the positive and negative terminals of the primary side of the LCC-LCC compensation network; the AC input side of the secondary active rectifier is connected to the positive and negative terminals of the secondary side of the LCC-LCC compensation network, and the DC output terminal of the secondary active rectifier is connected to the bus capacitor C bus The primary-secondary coupling coil L1 is connected to the output end of the primary side of the LCC-LCC compensation network, and the primary-secondary coupling coil L2 is connected to the output end of the secondary side of the LCC-LCC compensation network; the primary-secondary coupling coil L1 and the primary-secondary coupling coil L2 are coupled via a magnetic field;

[0022] The slow time scale structure further includes a subsequent FSBB converter, an output capacitor Co and a load Ro; the subsequent FSBB converter includes a power inductor L;

[0023] The input end of the subsequent FSBB converter is connected to the bus capacitor C bus In parallel, the output end of the latter FSBB converter is connected to the output capacitor C o In parallel, the output capacitor C o With the load R o in parallel.

[0024] Furthermore, the composite control unit further includes:

[0025] A scale determination module defines the fast time scale structure and the slow time scale structure, selects variables, and selects the rules of the full modal period and the unified time scale;

[0026] Correction module, used for correction of uniform time scale;

[0027] The target determination module is used to calculate the port energy and select the control target.

[0028] Furthermore, the scale determination module, wherein the definition of the fast time scale structure and the slow time scale structure and the selection of variables include:

[0029] The operating frequency of the fast time scale structure is f M The previous IPT system is defined as a fast time scale system, and the corresponding variables are fast time scale variables, specifically x = [i p u Cp u C1 i1 i2 u C2 u Cs i s ] T ;

[0030] The operating frequency of the FSBB converter of the slow time scale module is a slow time scale system, and the corresponding variable is a slow time scale variable, specifically z=[C bus i L u Co ] T .

[0031] Furthermore, the scale determination module, wherein the regular selection of the full modal period and the unified time scale includes:

[0032] The fast time scale system duty cycle is T M =1 / f M ; The working cycle of the slow time scale system is T N =1 / f N ;

[0033] Where, define T m is a unified time scale variable, satisfying Τ m =T M / σ M =T N / σ N , under the unified time scale, the sampling time of the fast time scale system is x f (ζ0)=x f (nT M ),x f (ζ1),x f (ζ2),xf (ζ3),x f (ζ4),x f ((n+1)T M ),…,x f (σ M σ N T M ),…;

[0034] The sampling time of the slow time scale system is z s (ζ0)=z s (nT N ),z s (ζ1),z s (ζ2),x s (ζ3),x s (ζ4),x s (ζ5),z s ((n+1)T M ),…,z f (σ M σ N T N ),…, satisfying Δζ i =ζ i -ζ i-1 =Τ m (i=1,2,…);

[0035] The full modal period is T max_com =σ M σ N Τ m =σ M T M =σ N T N .

[0036] Furthermore, the correction module includes:

[0037] The correction to a uniform time scale is defined as

[0038] in, is the unified time scale after correction, [Τ m ] means to select the closest feasible value that satisfies f m =1 / Τ m , T m is a unified time scale, where f m It needs to be an integer multiple of 1kHz; t d is the dead time, K0=0,±1,±2,….

[0039] Furthermore, the calculation of the port energy and the selection of the control target include:

[0040] Among them, the port energies of ports (a+, a-), (b+, b-), (c+, c-), and (d+, d-) are respectively expressed as:

[0041]

[0042] Where, E in|Tm Indicates the input port energy executed at a uniform time scale; U in is the DC input power supply, C p , C1 represents the capacitance of the primary LCC parallel series compensation capacitor, The corresponding capacitor voltage is The value of the moment;

[0043]

[0044] Where, E bus|Tm represents the input energy of the cascaded ports executed at a uniform time scale; U in is the DC input power supply, C p , C1 represents the capacitance of the primary LCC parallel series compensation capacitor, u Cbus is the bus capacitor voltage, i bus is the input current of the cascade port, i′ bus is the output current of the cascade port; σ M , σ N The fast time and slow time periods contain a unified time scale T m multiples; D1 is the duty cycle of the left bridge arm; α is the phase difference; L is the power inductance value; I L0 is the current value of the power inductor;

[0045]

[0046] Where, E′ bus|Tm represents the output energy of the cascaded ports executed at a uniform time scale; U in is the DC input power supply, C p , C1 represents the capacitance of the primary LCC parallel series compensation capacitor; u Cbus is the bus capacitor voltage, i bus is the input current of the cascade port, i′ bus is the output current of the cascade port;

[0047]

[0048] Where, E o|Tm Indicates the energy consumed by the load executed at a uniform time scale, u o 、i orepresents the output voltage and current of the dual-time-scale cascade system; D2 is the duty cycle of the right bridge arm;

[0049] The control target is selected by selecting the energy of the port (c+, c-) as the control target.

[0050] In a second aspect of the present application, a control method for a full-modal energy control system of a dual-time-scale cascade system is provided, comprising:

[0051] Initialization parameter U in 、U Cbus , D1, D2 and α; among them, U in is the input voltage, U Cbus is the bus capacitor voltage, D1 is the upper tube conduction duty cycle of the left bridge arm of the FSBB converter, D2 is the upper tube conduction duty cycle of the right bridge arm of the FSBB converter, and α is the phase difference;

[0052] Calculate the unified time scale T m and the full modal period E bus|Tm_ref (u Cbus );

[0053] Calculate the energy of ports (a+, a-) to (d+, d-) at a unified time scale within the full modal period;

[0054] Select the energy of the control object to port (c+, c-);

[0055] Port (c+, c-) energy reference value E bus|Tm_ref (u Cbus ) and the real-time calculated value E bus|Tm (u Cbus ) make a difference;

[0056] The input voltage regulator and current regulator go through the PWM pulse generation link and duty cycle adjustment link in sequence to obtain D1, D2 and α of the next full modal cycle.

[0057] Compared with the prior art, the present invention has at least one of the following beneficial effects:

[0058] (1) This application divides the system into a fast time scale structure IPT and a slow time scale structure FSBB through the design of a dual time scale cascade IPT-FSBB system, and optimizes the dynamic characteristics of different time scales respectively, thereby improving the system's adaptability to complex working conditions. At the same time, the voltage regulator and current regulator in the control circuit respectively adjust the slow and fast time scale structures in a targeted manner, the proportional link processes the fast time scale sampling value, and the composite control power supply and PWM generator generate precise pulse width modulation signals to control the system, ensuring the accuracy and stability of the system output signal to achieve precise distribution and regulation of system energy, thereby improving the energy utilization efficiency of the system and reducing energy loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Other features, objects and advantages of the present application will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0060] Figure 1 Schematic diagram of the structure of a full-modal energy composite control system in one embodiment of the present application.

[0061] Figure 2 It is a typical dual-time-scale cascade IPT-FSBB system in the prior art.

[0062] Figure 3 This is a block diagram of full-modal energy control in one embodiment of the present application.

[0063] Figure 4 It is a unified time scale sequence of all modal periods in one embodiment of the present application.

[0064] Figure 5 This is a flowchart of the execution of the full-modal energy control method in one embodiment of the present application.

[0065] Figure 6 This is a verification diagram of the dual-time-scale energy model in one embodiment of the present application.

[0066] Figure 7 This is a system waveform diagram of a traditional single-time-scale energy control strategy in one embodiment of the present application.

[0067] Figure 8 This is a waveform response diagram of full modal energy control based on a dual-time-scale energy model in one embodiment of the present application. DETAILED DESCRIPTION

[0068] The present application is described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present application, but are not intended to limit the present application in any form. It should be noted that those skilled in the art may make several variations and improvements without departing from the scope of the present application. These all fall within the scope of protection of the present application.

[0069] In the prior art, referring to Figure 2 As shown in Figure 1, the four-switch buck-boost (FSBB) converter includes power switches S1 through S4 and a power inductor L. D1 and D2 represent the conduction duty cycles of switches S1 and S2, respectively. S1 and S3, and S2 and S4, are complementary in conduction. Due to its voltage-increasing and voltage-decreasing capabilities, the FSBB converter is often used as a back-end converter in IPT systems to match the voltage levels of different energy storage batteries. Furthermore, the FSBB can also be used for peak efficiency tracking in front-end IPT systems.

[0070] Reference Figure 1 As shown, a full-modal energy control system of a dual-time-scale cascade system according to an embodiment of the present application includes: a dual-time-scale cascade IPT-FSBB system and a control circuit.

[0071] The dual-time-scale cascade IPT-FSBB system includes a fast-time-scale structure IPT and a slow-time-scale structure FSBB; the control circuit includes: a voltage regulator, a current regulator, a proportional link, a PWM generator and a composite control unit.

[0072] The input end of the current regulator is connected to the fast time scale structure IPT, the input end of the voltage regulator is connected to the slow time scale structure FABB, and the sampling value of the fast time scale structure IPT is connected to the input end of the composite control unit through a proportional link; the output ends of the current regulator and the voltage regulator are connected to the composite control unit, and the input end of the PWM generator is connected to the output end of the composite control unit, which is used to control the dual-time scale cascade IPT-FSBB system through the PWM generator.

[0073] Specifically, in the full-modal energy control system of the dual-time-scale cascade system, dual-time-scale energy collaborative management is achieved by adopting a hierarchical control architecture. The fast-time-scale structure IPT collects its own operating data in real time. The sampled values are first processed preliminarily by the proportional link and transmitted to the composite control unit. At the same time, the current regulator obtains the relevant signals of the fast-time-scale structure IPT as input. The slow-time-scale structure FSBB also collects its own data. The voltage regulator uses the signal of the slow-time-scale structure FSBB as input. The current regulator and the voltage regulator adjust the input signals respectively and send the adjusted output signals to the composite control unit. The composite control unit adjusts the signals from the proportional link, the current regulator and the voltage regulator, and sends control instructions to the PWM generator. The PWM generator modulates the duty cycle of the switching device according to the instructions. Finally, the signal is used to accurately control the dual-time-scale cascade IPT-FSBB system to achieve coordinated operation of the entire system under dual time scales.

[0074] In the above-mentioned embodiment of the present application, through the design of a dual-time-scale cascade IPT-FSBB system, the system is divided into a fast time-scale structure IPT and a slow time-scale structure FSBB, and the dynamic characteristics of different time scales are optimized respectively, thereby improving the system's adaptability to complex working conditions. At the same time, the voltage regulator and current regulator in the control circuit respectively perform targeted adjustments to the slow and fast time-scale structures, the proportional link processes the fast time-scale sampling value, and the composite control power supply and PWM generator generate precise pulse width modulation signals to control the system, ensuring the accuracy and stability of the system output signal to achieve precise distribution and regulation of system energy, thereby improving the energy utilization efficiency of the system and reducing energy loss.

[0075] In some specific embodiments, the fast time scale structure includes an LCC-LCC resonant compensation network, the primary side of the LCC-LCC compensation network is provided with a capacitor C1 and a capacitor Cp, and the sampling values of the capacitors C1 and Cp are passed through proportional links KC1 and KCp; the slow time scale structure includes a bus capacitor Cbus and a power inductor L, and the current sampling value iL of the power inductor L is adjusted by a current regulator and then input to the composite control unit; the bus capacitor C bus The bus voltage sampling value U Cbus After being adjusted by the voltage regulator, it is input to the composite control unit; an energy control module is provided in the composite control unit for realizing full-modal energy control through the cascade system energy control strategy.

[0076] Specifically, in the fast time scale structure, the primary side of the LCC-LCC resonant compensation network is configured with capacitors C1 and C p , real-time acquisition of the sampling value of the capacitor, respectively, the capacitor C1 and the capacitor C p The sampling value is sent to the corresponding proportional link KC1 and K Cp Proportional processing is performed, and the processed signal is transmitted to the composite control unit; in the slow time scale structure, the current sampling value iL of the power inductor L is obtained and input into the current regulator for adjustment, and the adjusted output signal is sent to the composite control unit; at the same time, the bus capacitor C bus The bus voltage sampling value U Cbus is collected and input into the voltage regulator, which then Cbus The signal is then regulated and input to the composite control unit. The composite control unit receives the signals from the fast and slow time scale structures and processes them using the cascade system energy control strategy preset within the energy control module to achieve energy distribution and control of the entire dual-time scale cascade system.

[0077] In the above embodiment, the sampled values of the primary-side capacitor C1 and the capacitor Cp of the LCC-LCC resonant compensation network are processed by a proportional link. In combination with the slow time scale structure, the current of the power inductor L and the voltage of the bus capacitor Cbus are adjusted separately. Through the cascade system energy control strategy set in the composite control unit, the operation of the fast and slow time scale structures can be comprehensively coordinated, the dynamic changes under the fast time scale can be accurately captured, and the response speed and control accuracy of the system under rapidly changing working conditions can be improved.

[0078] In the above embodiment, referring to Figure 1 As shown in FIG, the structural diagram of the full-modal energy composite control system includes a voltage PI regulation link, a current PI regulation link, and a capacitor-voltage proportional link.

[0079] Capacitor C of the primary LCC compensation network p , C1 sampling value u C1 、u Cp After the capacitor voltage ratio link, the input energy in the cascade system energy control strategy is calculated. Bus capacitor voltage sampling value u Cbus The voltage PI regulation phase calculates the downstream input energy at the cascade port and serves as the control variable for the full-modal cycle energy control strategy (cascade system energy control strategy). The inductor current sampling value of the downstream FSBB converter passes through the current regulation phase to output the downstream converter's required on-duty cycle, which also serves as a parameter for calculating the energy at ports (b+, b-), (c+, c-), and (d+, d-).

[0080] Reference Figure 2 As shown, the dual time scale cascade IPT-FSBB system also includes a DC input power supply U in , primary inverter, LCC-LCC resonant compensation network, coupling coils L1, L2, secondary active rectifier, bus electrolytic capacitor C bus, four-switch buck-boost converter, output capacitor C o , load R o The DC input power supply is connected to the primary inverter, and the AC output of the primary inverter is connected to the series compensation inductor L in the LCC-LCC compensation network. p The first input end is connected to the negative electrode of the parallel compensation capacitor, the output end of the secondary LCC compensation network is connected to the AC input side of the active rectifier, and the DC output side of the active rectifier is connected to the bus electrolytic capacitor C bus The system is connected in parallel and connected to a subsequent four-switch buck-boost converter. A control circuit is added to the traditional dual-time-scale cascaded IPT-FSBB system. A cascaded system energy control strategy is incorporated into the control circuit's composite control unit, eliminating load voltage and current sampling. This strategy regulates the on-duty cycle D1 of the upper transistor in the left arm of the FSBB converter, the on-duty cycle D2 of the upper transistor in the right arm of the FSBB converter, and the phase difference α between D1 and D2. This controls the on-off switching of the PWM generator's power switches, determines the converter's operating state, and accurately tracks dynamic changes in load switching, reducing the hardware design cost and complexity of the control system.

[0081] Among them, PWM-generator represents the PWM generator, that is, the switching signal driving pulse generator; Proposed Composite Control represents the composite control unit, which has a cascade system energy control strategy inside.

[0082] In some specific embodiments, the fast time scale structure further includes: a primary inverter, primary and secondary coupling coils L1 and L2, and a secondary active rectifier; the slow time scale structure further includes a post-stage FSBB converter, an output capacitor C o and load R o .

[0083] Specifically, the first output terminal and the second output terminal of the primary inverter are connected to the positive and negative terminals of the primary side of the LCC-LCC compensation network respectively; the AC input side of the secondary active rectifier is connected to the positive and negative terminals of the secondary side of the LCC-LCC compensation network, and the DC output terminal of the secondary active rectifier is connected to the bus capacitor C bus The primary and secondary coupling coils L1 and L2 are connected to the output end of the primary side of the LCC-LCC compensation network, and the primary and secondary coupling coils L2 are connected to the output end of the secondary side of the LCC-LCC compensation network; the primary and secondary coupling coils L1 and L2 are coupled by a magnetic field; the input end of the subsequent FSBB converter is connected to the bus capacitor C bus In parallel, the output of the subsequent FSBB converter and the output capacitor C o In parallel, the output capacitor C o With the load R o in parallel.

[0084] It should be noted that the power inductor L is located in the subsequent FSBB converter.

[0085] Among them, the working frequency of the fast time scale structure is f M , the slow time scale structure working frequency is f N .

[0086] Specifically, refer to Figure 1 As shown, the fast time scale structure includes an input DC power supply U in The primary inverter includes a power field effect tube Q 11 ~Q 14 The first output terminal and the second output terminal of the primary inverter are respectively connected to the positive and negative terminals of the primary side of the LCC-LCC compensation network.

[0087] The secondary side active rectifier includes power field effect transistor Q 21 ~Q 24 , the positive and negative terminals of the secondary side of the LCC-LCC compensation network are connected to the AC input side of the secondary active rectifier respectively.

[0088] The DC output terminal of the secondary active rectifier and the bus capacitor C bus connected.

[0089] The FSBB converter includes power field effect transistors S1 to S4 and a power inductor L.

[0090] The load link includes the output capacitor C o and the load resistor R o .

[0091] Reference Figure 1 As shown, in some specific embodiments, the slow time scale FSBB achieves the minimum current required for zero voltage switching ZVS operation -I L_ZVS =-2C oss U Cbus / t d Among them, C oss is the output capacitance, t d is the dead time; the current sampling value iL and the minimum current -I L_ZVS The difference between them is input into the current regulator, and the output result of the current regulator is D'1, which is the first input variable of the energy control module and is used to output the conduction duty cycle of the subsequent converter required by the energy control strategy of the cascade system in the next cycle; the bus voltage sampling value U Cbus With reference value U Cbus refThe difference between them is input into the voltage regulator, and the output result of the voltage regulator is used as the second input variable of the energy control module to calculate the subsequent input energy of the energy control strategy port of the cascade system; capacitor C1 and capacitor C p The sampling value is proportional to the K C1 and K Cp The output results are used as the third and fourth input variables of the full-modal energy control strategy to calculate the input energy in the cascade system energy control strategy.

[0092] Specifically, the proportional link K of the control circuit C1 Connected to the primary side capacitor C1 of the LCC-LCC compensation network in the power circuit, the proportional link K Cp Connected to the capacitor C2 on the primary side of the LCC-LCC compensation network; the bus capacitor C in the voltage regulator and the power circuit bus The current regulator is connected to the output of the FSBB converter to set the minimum current required for the FSBB to achieve ZVS operation -I L_ZVS =-2C oss U Cbus / t d ; Current sampling value iL and minimum current -I L_ZVS The comparison result is input to the current regulator.

[0093] The first input variable is used to ensure the ZVS operation of the subsequent FSBB system. The second input variable is used to calculate the control object, that is, the parameters of the energy of the cascade port (c+, c-). The third and fourth input variables are used to calculate the input energy of the dual-time-scale cascade system.

[0094] In some possible embodiments, the composite control unit further includes: a scale determination module for defining the fast time scale structure and the slow time scale structure and selecting variables, as well as selecting the rules of the full modal period and the unified time scale; a correction module for correcting the unified time scale; and a target determination module for calculating the port energy and selecting the control target.

[0095] Specifically, the scale determination module, in which the definition of fast time scale structure and slow time scale structure and the selection of variables include:

[0096] The operating frequency of the fast time scale structure is f M The previous IPT system is defined as a fast time scale system, and the corresponding variables are fast time scale variables, specifically x = [i p u Cp u C1 i1 i2 u C2 u Cs i s ]T ;

[0097] The operating frequency of the back-stage FSBB converter of the slow time scale module is a slow time scale system, and the corresponding variable is a slow time scale variable, specifically z=[C bus i L u Co ] T .

[0098] Reference Figure 4 As shown, specifically, the scale determination module, in which the regular selection of the full modal period and the unified time scale includes: the working period of the fast time scale system is T M =1 / f M ; The working period of the slow time scale system is T N =1 / f N .

[0099] Where, define T m is a unified time scale variable, satisfying Τ m =T M / σ M =T N / σ N , under the unified time scale, the sampling time of the fast time scale system is x f (ζ0)=x f (nT M ),x f (ζ1),x f (ζ2),x f (ζ3),x f (ζ4),x f ((n+1)T M ),…,x f (σ M σ N T M ),….

[0100] The sampling time of the slow time scale system is z s (ζ0)=z s (nT N ),z s (ζ1),z s (ζ2),x s (ζ3),x s (ζ4),x s (ζ5),z s ((n+1)T M ),…,z f (σ M σ N T N ),…, satisfying Δζ i =ζi -ζ i-1 =Τ m (i=1,2,…).

[0101] Among them, the calculation formula for the full modal period is T max com =σ M σ N Τ m =σ M T M =σ N T N ; Calculated based on the operating frequency of the dual time scale, it is essentially the least common multiple period.

[0102] Specifically, the correction module includes:

[0103] The correction formula for the unified time scale is defined as in is the unified time scale after correction, [Τ m ] means to select the closest feasible value that satisfies f m =1 / Τ m , T m is a unified time scale, where f m It needs to be an integer multiple of 1kHz; t d is the dead time, K0=0,±1,±2,….

[0104] Specifically, the target determination module is used to calculate the port energy and select the control target, including:

[0105] Among them, the port energies of ports (a+, a-), (b+, b-), (c+, c-), and (d+, d-) are expressed as follows:

[0106]

[0107] Where, E in|Tm Indicates the input port energy executed at a uniform time scale; U in is the DC input power supply, C p , C1 represents the capacitance of the primary LCC parallel series compensation capacitor, The corresponding capacitor voltage is The value of the moment;

[0108]

[0109] Where, E bus|Tm represents the input energy of the cascaded ports executed at a uniform time scale; U in is the DC input power supply, C p, C1 represents the capacitance of the primary LCC parallel series compensation capacitor; u Cbus is the bus capacitor voltage, i bus is the input current of the cascade port, i′ bus is the output current of the cascade port; σ M , σ N The fast time and slow time periods contain a unified time scale T m multiples; D1 is the duty cycle of the left bridge arm; α is the phase difference; L is the power inductance value; I L0 is the current value of the power inductor;

[0110]

[0111] Where, E′ bus|Tm represents the output energy of the cascaded ports executed at a uniform time scale; U in is the DC input power supply, C p , C1 represents the capacitance of the primary LCC parallel series compensation capacitor; u Cbus is the bus capacitor voltage, i bus is the input current of the cascade port, i′ bus is the output current of the cascade port;

[0112]

[0113] Where, E o|Tm Indicates the energy consumed by the load executed at a uniform time scale, u o 、i o represents the output voltage and current of the dual-time-scale cascade system; D2 is the duty cycle of the right bridge arm;

[0114] Selection of control target, select the energy of port (c+, c-) as the control target.

[0115] It should be noted that for accurate control, the bus capacitor voltage must be accurately sampled, and the output port energy can be obtained without the help of load voltage and current. If the output port energy is controlled, the load needs to be sampled, which increases the hardware design cost. If the input port energy is controlled, the dynamic response of the load current cannot be accurately tracked.

[0116] For a dual-time-scale cascade system, the busbar electrolytic capacitor's capacitance decreases with age and ambient temperature, leading to increased busbar voltage ripple. The output energy of the front-stage system is not fully transferred to the back-stage system; some energy interacts within the busbar capacitor. Furthermore, the back-stage system's output current, or load current, can be calculated using the output energy expression (4). To reduce sampling variables and lower hardware circuit design costs, the cascade port energy is selected as the control target.

[0117] Reference Figure 3 As shown, the input reference variable is E bus|Tm_ref (u Cbus ), the calculated value is compared with the reference value and the result is the PI regulator G c (s) input, the output of the PI regulator is used as the PWM pulse modulation link G PWM1 (s) and G PWM2 (s), G PWM1 (s) and G PWM2 (s) output as duty cycle adjustment G d1_uCbus (s) and G d2_uCbus (s) input.

[0118] The PWM signal is driven and sent to the power circuit; the PWM signal drives the power switch in the power circuit to turn on and off, determining the working state of the converter.

[0119] Specifically, the energy reference value E of the port (c+, c-) is determined according to the unified time scale and the rated bus voltage: bus|Tm_ref (u Cbus ), and then input the energy of the PI regulator G after the difference between it and the energy of the port (c+, c-) calculated in real time c (s); PI regulator G c The output of (s) is used as the PWM pulse modulation link G PWM1 (s) and G PWM2 (s) is input, and the duty cycle of the FSBB converter is output through the cascade system control strategy, which is input to the PWM generator, that is, the switching signal driving pulse generator. The output of the PWM pulse modulation link is used as the duty cycle adjustment link G d1_uCbus (s) and G d2_uCbus The input of (s) determines the conduction duty cycle of switches S1 and S2 in the next full-mode working cycle; the current source I bus (s) through the current regulator G Ibus_uCbus The output of (s) is summed with the output of the duty cycle regulator to determine the energy at ports (c+, c-) for the next full modal cycle.

[0120] Reference Figure 5 As shown, the second aspect of the present application provides a control method for a full-modal energy control system of a dual-time-scale cascade system, comprising:

[0121] Initialization parameter U in ,U Cbus ,D1,D2 and α; among them, U in is the input voltage, U Cbus is the bus capacitor voltage, D1 is the upper tube conduction duty cycle of the left bridge arm of the FSBB converter, D2 is the upper tube conduction duty cycle of the right bridge arm of the FSBB converter, and α is the phase difference;

[0122] Calculate the unified time scale T m and the full modal period E bus|Tm_ref (u Cbus );

[0123] Calculate the energy of ports (a+, a-) to (d+, d-) at a unified time scale within the full modal period;

[0124] Select the energy of the control object to port (c+, c-);

[0125] Port (c+, c-) energy reference value E bus|Tm_ref (u Cbus ) and the real-time calculated value E bus|Tm (u Cbus ) make a difference;

[0126] The input voltage regulator and current regulator go through the PWM pulse generation link and duty cycle adjustment link in sequence to obtain D1, D2 and α of the next full modal cycle.

[0127] In the above embodiments of the present application, the dynamic response capability and steady-state accuracy of the complex energy system are improved through the dual-time scale cascade design and full-modal energy closed-loop control. Through the cascade design of the unified time scale (Tm) and the full-modal period (Ebus|Tm_ref), hierarchical control of fast-changing parameters (such as transient power fluctuations) and slow-changing parameters (such as bus energy balance) is achieved to avoid multi-modal coupling oscillations; based on the full-modal period calculation of the port (a+~d-) energy, the energy distribution requirements under different working conditions are dynamically matched, and the directional control of the (c+, c-) port is used to achieve accurate tracking of the key node energy; the use of PI regulator and dynamic duty cycle adjustment can compensate for nonlinear disturbances (such as load mutations or input voltage fluctuations) in real time to achieve rapid stabilization of the system.

[0128] Specifically, the key parameters (input voltage Uin, bus capacitor voltage UCbus, duty cycle D1 / D2 and phase difference α) are initialized first, and the unified time scale Tm and full modal energy period E are calculated based on the two different operating frequencies of the cascade system, that is, the fast and slow time scales. bus|Tm_ref (u Cbus ), synchronize the energy flows of sub-modules at different time scales, then calculate the modal energy distribution of each port (a±~d±) in real time within a unified time frame, and select port (c+,c-) as the core control object; by comparing the theoretical reference value of the port energy with the actual measured value, an error signal is generated and input into the PI regulator. The control parameters D1, D2 and α are iteratively updated through PWM modulation and duty cycle optimization algorithm, forming a closed-loop feedback, so that the system can achieve active reconstruction of the energy distribution within the next full modal cycle.

[0129] In one embodiment of the application, the parameters are set as follows:

[0130] Input voltage: 100-400V, DC;

[0131] Output power: hundreds of watts to 2.5kW;

[0132] Working frequency: 85kHz for front stage, 20 / 45 / 85kHz for rear stage;

[0133] Power inductor: 55μH;

[0134] Transmitting coil self-inductance L1: 75.7μH;

[0135] Receiving coil self-inductance L2: 77.5μH;

[0136] Primary side series compensation inductor Lp: 41.5μH;

[0137] Primary side series compensation capacitor C1: 102.5nF;

[0138] Primary side parallel compensation capacitor Cp: 83.7nF;

[0139] Secondary side series compensation inductor Ls: 41.5μH;

[0140] Secondary side series compensation capacitor C2: 97.4nF;

[0141] Secondary side parallel compensation capacitor Cs: 84.5nF;

[0142] DSP:TMS320F28335.

[0143] Bus capacitance Cbus: 5μF;

[0144] Output capacitor Co: 100μF;

[0145] SiC FET S1~S4: C3M0021120K, Coss=180pF@(Tc=25℃, VDS=1000V),

[0146] RDS(on)=38mΩ@(VGS=15V, ID=50A, TJ=175℃)

[0147] The corresponding dual-time-scale cascade IPT-FSBB system adopts the traditional single-time-scale energy control and the full-modal energy control strategy based on the dual-time-scale energy model proposed in this application. Figure 6 、 Figure 7 、 Figure 8Experimental results show that when using a traditional control strategy based on a single-time-scale energy model, the corresponding slow time scales fN = 20kHz, 45kHz, and 85kHz, when the load voltage suddenly changes from 300V to 400V, the adjustment time is 34ms, 36ms, and 31ms, respectively, accompanied by output current undershoot and overshoot. Using a full-modal control strategy based on a dual-time-scale energy model, the corresponding adjustment time is 19ms, 16ms, and 9ms, and smooth load switching is achieved without overshoot.

[0148] It can be seen that this embodiment uses the port energy as the control target, which can accurately track the response waveform of the system when the load changes and reduce the transient adjustment time.

[0149] The above describes the specific embodiments of the present application. It should be understood that the present application is not limited to the specific embodiments described above, and those skilled in the art may make various modifications or variations within the scope of the claims, which do not affect the substantive content of the present application. The above preferred features may be used in any combination as long as they do not conflict with each other.

Claims

1. A full-modal energy control system of a dual-time-scale cascade system, characterized in that: Includes: dual-time-scale cascade IPT-FSBB system and control circuit; The dual-time-scale cascade IPT-FSBB system includes a fast-time-scale structure IPT and a slow-time-scale structure FSBB; The control circuit includes: a voltage regulator, a current regulator, a proportional link, a PWM generator and a composite control unit; The input end of the current regulator is connected to the fast time scale structure IPT, the input end of the voltage regulator is connected to the slow time scale structure FABB, and the sampling value of the fast time scale structure IPT is connected to the input end of the composite control unit via the proportional link; The output ends of the current regulator and the voltage regulator are connected to the composite control unit, and the input end of the PWM generator is connected to the output end of the composite control unit, for controlling the dual-time-scale cascaded IPT-FSBB system through the PWM generator.

2. The full modal energy control system of a dual time scale cascade system according to claim 1, characterized in that: The fast time scale structure includes an LCC-LCC resonant compensation network, wherein the primary side of the LCC-LCC compensation network is provided with a capacitor C1 and a capacitor C p , the capacitor C1 and the capacitor C p The sampling value is passed through the proportional link K C1 and K Cp ; The slow time scale structure includes a bus capacitor C bus and power inductor L; The current sampling value iL of the power inductor L is adjusted by the current regulator and then input into the composite control unit; the bus capacitor C bus The bus voltage sampling value U Cbus After being regulated by the voltage regulator, it is input into the composite control unit; An energy control module is provided in the composite control unit for realizing full-modal energy control through a cascade system energy control strategy.

3. The full modal energy control system of a dual time scale cascade system according to claim 2, characterized in that: The slow time scale FSBB achieves the minimum current required for zero voltage switching ZVS operation -I L_ZVS =-2C oss U Cbus / t d ; Among them, C oss is the output capacitance, t d is the dead time; The current sampling value iL and the minimum current -I L_ZVS The difference after comparison is input into the current regulator, and the output result of the current regulator is the first input variable of the energy control module, which is used to output the conduction duty cycle of the subsequent converter of the slow time scale structure required by the energy control strategy of the cascade system in the next cycle; The bus voltage sampling value U Cbus With reference value U Cbus_ref The difference after comparison is input into the voltage regulator, and the output result of the voltage regulator is used as the second input variable of the energy control module to calculate the subsequent input energy of the energy control strategy port of the cascade system; The capacitor C1 and the capacitor C p The sampling value is passed through the proportional link K C1 and K Cp The output results are used as the third input variable and the fourth input variable of the full modal energy control, and are used to calculate the input energy in the energy control strategy of the cascade system.

4. The full modal energy control system of a dual time scale cascade system according to claim 3, characterized in that: The fast time scale structure also includes a primary side inverter, primary and secondary side coupling coils L1 and L2, and a secondary side active rectifier; The first output terminal and the second output terminal of the primary inverter are respectively connected to the positive and negative terminals of the primary side of the LCC-LCC compensation network; the AC input side of the secondary active rectifier is connected to the positive and negative terminals of the secondary side of the LCC-LCC compensation network, and the DC output terminal of the secondary active rectifier is connected to the bus capacitor C bus The primary-secondary coupling coil L1 is connected to the output end of the primary side of the LCC-LCC compensation network, and the primary-secondary coupling coil L2 is connected to the output end of the secondary side of the LCC-LCC compensation network; the primary-secondary coupling coil L1 and the primary-secondary coupling coil L2 are coupled via a magnetic field; The slow time scale structure also includes a post-stage FSBB converter, an output capacitor C o and load R o ; The input end of the subsequent FSBB converter is connected to the bus capacitor C bus In parallel, the output end of the latter FSBB converter is connected to the output capacitor C o In parallel, the output capacitor C o With the load R o in parallel.

5. The full modal energy control system of a dual time scale cascade system according to claim 4, characterized in that: The composite control unit further includes: A scale determination module defines the fast time scale structure and the slow time scale structure, selects variables, and selects the rules of the full modal period and the unified time scale; Correction module, used for correction of uniform time scale; The target determination module is used to calculate the port energy and select the control target.

6. The full modal energy control system of a dual time scale cascade system according to claim 5, characterized in that: The scale determination module, wherein the definition of the fast time scale structure and the slow time scale structure and the selection of variables include: The operating frequency of the fast time scale structure is f M The previous IPT system is defined as a fast time scale system, and the corresponding variables are fast time scale variables, specifically x = [i p u Cp u C1 i1 i2 u C2 u Cs i s ] T ; The operating frequency of the FSBB converter of the slow time scale module is a slow time scale system, and the corresponding variable is a slow time scale variable, specifically z=[C bus i L u Co ] T .

7. The full modal energy control system of a dual time scale cascade system according to claim 5, characterized in that: The scale determination module, wherein the regular selection of the full modal period and the unified time scale includes: The fast time scale system duty cycle is T M =1 / f M ; The working cycle of the slow time scale system is T N =1 / f N ; Where, define T m is a unified time scale variable, satisfying Τ m =T M / σ M =T N / σ N , under the unified time scale, the sampling time of the fast time scale system is x f (ζ0)=x f (nT M ),x f (ζ1),x f (ζ2),x f (ζ3),x f (ζ4),x f ((n+1)T M ),…,x f (σ M σ N T M ),…; The sampling time of the slow time scale system is z s (ζ0)=z s (nT N ),z s (ζ1),z s (ζ2),x s (ζ3),x s (ζ4),x s (ζ5),z s ((n+1)T M ),…,z f (σ M σ N T N ),…, satisfying Δζ i =ζ i -ζ i-1 =Τ m (i=1,2,…); The full modal period is T max_com =σ M σ N T m =σ M T M =σ N T N .

8. The full modal energy control system of a dual time scale cascade system according to claim 5, characterized in that: The correction module includes: The correction formula for the unified time scale is defined as in, is the unified time scale after correction, [Τ m ] means to select the closest feasible value that satisfies f m =1 / Τ m , T m is a unified time scale, where f m It needs to be an integer multiple of 1kHz; t d is the dead time, K0=0,±1,±2,….

9. The full modal energy control system of a dual time scale cascade system according to claim 5, characterized in that: The target determination module is used to calculate the port energy and select the control target. include: The ports include (a+, a-), (b+, b-), (c+, c-), and (d+, d-), and the port energies are expressed as follows: Where, E in|Tm U represents the input port energy executed at a uniform time scale; in is the DC input power supply, C p , C1 represents the capacitance of the primary LCC parallel series compensation capacitor, The corresponding capacitor voltage is The value of the moment; Where, E bus|Tm represents the input energy of the cascaded ports executed at a uniform time scale, U in is the DC input power supply, C p , C1 represents the capacitance of the primary LCC parallel series compensation capacitor, u Cbus is the bus capacitor voltage, i bus is the input current of the cascade port, i′ bus is the output current of the cascade port; σ M , σ N The fast time and slow time periods contain a unified time scale T m multiples; D1 is the duty cycle of the left bridge arm; α is the phase difference; L is the power inductance value; I L0 is the current value of the power inductor; Where, E′ bus|Tm represents the output energy of the cascaded ports executed at a uniform time scale; U in is the DC input power supply, C p , C1 represents the capacitance of the primary LCC parallel series compensation capacitor, u Cbus is the bus capacitor voltage, i bus is the input current of the cascade port, i′ bus is the output current of the cascade port; Where, E o|Tm Indicates the energy consumed by the load executed at a uniform time scale, u o 、i o represents the output voltage and current of the dual-time-scale cascade system; D2 is the duty cycle of the right bridge arm; The control target is selected by selecting the energy of the port (c+, c-) as the control target.

10. A control method for a full modal energy control system of a dual time scale cascade system according to any one of claims 1 to 9, characterized in that: include: Initialization parameter U in 、U Cbus , D1, D2 and α; Among them, U in is the input voltage, U Cbus is the bus capacitor voltage, D1 is the upper tube conduction duty cycle of the left bridge arm of the FSBB converter, D2 is the upper tube conduction duty cycle of the right bridge arm of the FSBB converter, and α is the phase difference; Calculate the unified time scale T m and the full modal period E bus|Tm_ref (u Cbus ); Calculate the energy of ports (a+, a-) to (d+, d-) at a unified time scale within the full modal period; Select the energy of the control object to port (c+, c-); Port (c+, c-) energy reference value E bus|Tm_ref (u Cbus ) and the real-time calculated value E bus|Tm (u Cbus ) to make a mistake; The input voltage regulator and current regulator go through the PWM pulse generation link and duty cycle adjustment link in sequence to obtain D1, D2 and α of the next full modal cycle.

Images