New energy vehicle DC-DC converter output control method and system

Abstract

The invention relates to the technical field of vehicle voltage output control, and particularly discloses a new energy vehicle DC-DC converter output control method and system, and the method comprises the steps: obtaining a Buck circuit output voltage, and comparing the output voltage with a set voltage, so as to obtain a voltage error and an error change rate; establishing a voltage loop Fuzzy-ADRC control structure of the output voltage of the Buck circuit so as to perform fuzzy control and active disturbance rejection control on the output voltage of the Buck circuit; and the voltage loop Fuzzy-ADRC control structure carries out real-time and accurate estimation and compensation on the total disturbance of the output current of the Buck circuit according to the voltage error and the error change rate. The stability, the response speed and the voltage output precision of the DC-DC converter system of the new energy vehicle can be improved, and the energy consumption of the whole vehicle is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle voltage output control, and more specifically, to an output control method and system for a DC-DC converter of a new energy vehicle. Background Art

[0002] The low-voltage platform of a new energy vehicle generally refers to the system in the vehicle that supplies power to various auxiliary electrical devices, including but not limited to headlights, in-vehicle infotainment systems, electric windows, sensors, control modules, air conditioners, on-board diagnostic systems, etc. With the development of new energy vehicle technology, the design and voltage level of the low-voltage platform have also changed to adapt to new electrical requirements and improve overall performance. Currently, traditional fuel vehicles usually use a 12V low-voltage system, while new energy vehicles generally adopt 24V as the low-voltage platform of the whole vehicle considering power demand, energy-saving efficiency, intelligence, and technological maturity. However, due to industry standards, cost-effectiveness, and some specific equipment requirements, some parts of the whole vehicle still need 12V power supply.

[0003] Currently, vehicle manufacturers usually use a DC-DC converter to convert the low-voltage 24V into 12V to supply power to some 12V component devices. However, since the existing buck circuit adopts open-loop control or closed-loop control based on PID; among them, open-loop control cannot perform feedback regulation on the system, resulting in the output voltage being difficult to be stabilized at the set value, and it cannot cope with complex load changes and input voltage fluctuations. Although the buck circuit based on PID closed-loop control can improve the system stability and response speed, improper parameter setting of PID control may lead to system instability, oscillation or overshoot phenomenon, and it is difficult to achieve the best control effect.

[0004] Therefore, how to perform real-time observation and compensation on the output voltage and external disturbances of the DC-DC converter, achieve stable control of the entire DC-DC converter system, and improve the stability, response speed, and voltage output accuracy of the entire system is of great significance. Summary of the Invention

[0005] The present invention provides an output control method and system for a DC-DC converter of a new energy vehicle, which solves the problem that the output voltage of the existing DC-DC converter for a new energy vehicle to supply power to low-voltage components is difficult to be stabilized, can improve the stability, response speed, and voltage output accuracy of the DC-DC converter system of a new energy vehicle, and reduce the energy consumption of the whole vehicle.

[0006] To achieve the above objectives, the present invention provides the following technical solutions:

[0007] An output control method for a DC-DC converter of a new energy vehicle, comprising:

[0008] Obtain the output voltage of the Buck circuit, and compare the output voltage with a set voltage to obtain a voltage error and an error change rate;

[0009] Establish a voltage-loop Fuzzy-ADRC control structure for the output voltage of the Buck circuit to perform fuzzy control and active disturbance rejection control on the output voltage of the Buck circuit;

[0010] The voltage-loop Fuzzy-ADRC control structure estimates and compensates the total disturbance of the output current of the Buck circuit in real time and accurately according to the voltage error and the error change rate.

[0011] Preferably, it further includes:

[0012] Construct a current-loop Fuzzy-PID control structure for the output current of the Buck circuit to generate a corresponding PWM drive signal according to the current error between the actual output current and the compensated reference current of the Buck circuit;

[0013] Precisely control the conduction or turn-off of the switching tube of the Buck circuit according to the PWM drive signal, so that the Buck circuit can respond quickly and maintain the stability of the output voltage in the face of load changes and input voltage fluctuations.

[0014] Preferably, the establishment of the voltage-loop Fuzzy-ADRC control structure for the output voltage of the Buck circuit includes:

[0015] Establish a first fuzzy controller and an ADRC controller, use the voltage error and the error change rate as two input variables of the first fuzzy controller, and use the correction value of the parameter to be tuned in the ADRC controller as the output variable, so that the fuzzy controller can perform real-time tuning and optimization of the ADRC parameters of the ADRC controller.

[0016] Preferably, the construction of the current-loop Fuzzy-PID control structure for the output current of the Buck circuit includes:

[0017] Establish a second fuzzy controller and a PID controller, use the current error as the input variable of the second fuzzy controller, and use the kp, ki, and kd of the PID controller as the output variables, so that the duty cycle of the PWM wave output by the PID controller generates a corresponding PWM drive signal as the error between the output and the given voltage changes.

[0018] Preferably, the establishment of the ADRC controller includes:

[0019] Establish the mathematical models corresponding to the tracking differentiator TD, the nonlinear state error feedback NLSEF, and the extended state observer ESO. Regard uncertainties and internal and external disturbances as the total disturbance of the system, and estimate and compensate for the total disturbance through the nonlinear state error feedback NLSEF and the extended state observer ESO.

[0020] Preferably, both the first fuzzy controller and the second fuzzy controller are single-variable two-dimensional fuzzy controllers.

[0021] The present invention also provides an output control system for a new energy vehicle DC-DC converter, which uses the above control method and includes: a Buck circuit module, a voltage signal acquisition module, and a Fuzzy-ADRC controller;

[0022] The input end of the voltage signal acquisition module is connected to the output end of the Buck circuit module, and the output end of the voltage signal acquisition module is connected to the input end of the Fuzzy-ADRC controller to construct a voltage-loop Fuzzy-ADRC control structure, enabling the Fuzzy-ADRC controller to accurately estimate and compensate for the total disturbance of the output current of the Buck circuit in real time.

[0023] Preferably, it further includes: a Fuzzy-PID controller and a PWM drive module;

[0024] The input end of the PWM drive module is connected to the output end of the Fuzzy-PID controller, and the output end of the PWM drive module is connected to the control end of the switching power supply of the Buck circuit to construct a current-loop Fuzzy-ADRC control structure, enabling the Fuzzy-PID controller to generate a corresponding PWM drive signal according to the current error between the actual output current of the Buck circuit and the compensated reference current.

[0025] Preferably, it further includes: a current acquisition module;

[0026] The input end of the current acquisition module is connected to the output end of the Buck circuit module, and the output end of the current acquisition module is connected to the input end of the Fuzzy-PID controller. The current acquisition module real-time acquires the actual output current of the Buck circuit;

[0027] The input end of the Fuzzy-PID controller is further connected to the output end of the Fuzzy-ADRC controller.

[0028] Preferably, the PWM drive module is a PWM wave generator.

[0029] The present invention provides a method and system for controlling the output of a DC-DC converter in a new energy vehicle. A voltage-loop Fuzzy-ADRC control structure is constructed based on a Buck circuit to improve the dynamic response and anti-disturbance ability of the system. At the same time, a current-loop Fuzzy-PID control structure is constructed to generate corresponding PWM drive signals to accurately control the conduction and cut-off of the switching tubes of the Buck circuit, thereby ensuring the stability and efficiency of the entire system. It solves the problem that the output voltage of the existing DC-DC converter in a new energy vehicle is difficult to stabilize when supplying power to low-voltage components, and can improve the stability, response speed and voltage output accuracy of the DC-DC converter system in a new energy vehicle, and reduce the energy consumption of the whole vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the specific embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below.

[0031] Figure 1 It is a schematic diagram of a method for controlling the output of a DC-DC converter in a new energy vehicle provided by the present invention.

[0032] Figure 2 It is a schematic structural diagram of a system for controlling the output of a DC-DC converter in a new energy vehicle provided by an embodiment of the present invention.

[0033] Figure 3 It is a schematic structural diagram of a fuzzy controller provided by an embodiment of the present invention.

[0034] Figure 4 It is a schematic structural diagram of an ADRC controller provided by an embodiment of the present invention.

[0035] Figure 5 It is a schematic structural diagram of a Fuzzy-ADRC controller provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] In order to enable those skilled in the art to better understand the solutions of the embodiments of the present invention, the embodiments of the present invention will be further described in detail below in conjunction with the drawings and embodiments.

[0037] Aiming at the problem that the 12V power supply of the current DC-DC converter in a new energy vehicle to low-voltage components is difficult to stabilize, the present invention provides a method and system for controlling the output of a DC-DC converter in a new energy vehicle, which solves the problem that the output voltage of the existing DC-DC converter in a new energy vehicle is difficult to stabilize when supplying power to low-voltage components, and can improve the stability, response speed and voltage output accuracy of the DC-DC converter system in a new energy vehicle, and reduce the energy consumption of the whole vehicle.

[0038] As Figure 1 shown, a method for controlling the output of a DC-DC converter in a new energy vehicle includes:

[0039] S1: Obtain the output voltage of the Buck circuit, and compare the output voltage with a set voltage to obtain a voltage error and an error change rate.

[0040] S2: Establish a voltage-loop Fuzzy-ADRC control structure for the output voltage of the Buck circuit to perform fuzzy control and active disturbance rejection control on the output voltage of the Buck circuit.

[0041] S3: The voltage-loop Fuzzy-ADRC control structure performs real-time and accurate estimation and compensation on the total disturbance of the output current of the Buck circuit according to the voltage error and the error change rate.

[0042] Specifically, as Figure 2 shown, the Buck circuit is composed of an inductor L, a capacitor C, a diode D, a MOSFET tube, and a load R, and the input voltage U d is transformed into U0. The DC-DC converter is mainly based on the Buck circuit. In new energy vehicles, the DC-DC converter converts the 24V of the vehicle's low-voltage platform into 12V to supply power to some 12V components. This method constructs a voltage fuzzy active disturbance rejection control based on the Buck circuit to improve the dynamic response and anti-disturbance ability of the system. As Figure 2 shown, the voltage fuzzy active disturbance rejection control adopts a Fuzzy-ADRC control structure. A voltage-loop Fuzzy-ADRC control structure is constructed at the output end of the Buck circuit to perform fuzzy control and active disturbance rejection control on the output voltage of the Buck circuit. The voltage-loop Fuzzy-ADRC control structure compares the output voltage of the Buck circuit with the set voltage to obtain a voltage error e and a voltage error change rate ec, and uses the voltage error e and the voltage error change rate ec as input variables of the voltage-loop Fuzzy-ADRC control structure for fuzzy active disturbance rejection control to achieve real-time and accurate estimation and compensation of the total disturbance of the output current of the Buck circuit.

[0043] This method further includes:

[0044] S4: Construct a current-loop Fuzzy-PID control structure for the output current of the Buck circuit to generate a corresponding PWM drive signal according to the current error between the actual output current and the compensated reference current of the Buck circuit.

[0045] S5: Accurately control the conduction or cutoff of the switching tube of the Buck circuit according to the PWM drive signal, so that the Buck circuit can quickly respond and maintain the stability of the output voltage in the face of load changes and input voltage fluctuations.

[0046] Specifically, as Figure 2As shown, a current-loop Fuzzy-PID control structure is also constructed based on the Buck circuit, forming a double-loop control structure of voltage-loop Fuzzy-ADRC and current-loop Fuzzy-PID for the Buck circuit. The current-loop Fuzzy-PID control structure performs fuzzy PID control on the actual output current i of the Buck circuit and the reference current i after compensation by the voltage-loop Fuzzy-ADRC control structure. ref The current-loop Fuzzy-PID control structure generates a corresponding PWM drive signal according to the current error between the actual output current and the compensated reference current of the Buck circuit to precisely control the on and off of the switching tube of the Buck circuit, thereby ensuring the stability and efficiency of the entire system. This double-loop control structure can improve the performance of the Buck circuit, especially in the face of load changes and input voltage fluctuations, and can quickly respond and maintain the stability of the output voltage. In addition, the parameters of the PID controller and the active disturbance rejection controller are tuned and optimized through the fuzzy control theory to achieve the best control effect.

[0047] Furthermore, the voltage-loop Fuzzy-ADRC control structure for establishing the output voltage of the Buck circuit includes:

[0048] Establish a first fuzzy controller and an ADRC controller, use the voltage error and the error change rate as the two input variables of the first fuzzy controller, and use the correction value of the parameter to be tuned in the ADRC controller as the output variable, so that the fuzzy controller can perform real-time tuning and optimization of the ADRC parameters of the ADRC controller.

[0049] In practical applications, as Figure 3 shown, the core idea of the fuzzy control of the fuzzy controller is to transform the past experience control method of people into a language that can be received by a computer, and formulate a series of control rules through fuzzy reasoning, so as to better achieve the control of the controlled object. Figure 3 As shown in, the two-dimensional fuzzy controller mainly consists of four parts: fuzzy processing, fuzzy reasoning, rule base, and defuzzification. The role of fuzzy processing is to convert the input error e and error change rate ec into fuzzy quantities; fuzzy reasoning is to use the fuzzy rule base to perform fuzzy reasoning on the fuzzy quantities obtained by fuzzy processing to obtain the control quantity; defuzzification, that is, anti-fuzzyification, changes the control quantity obtained by fuzzy reasoning and the like into the precise control quantity in the actual operation process.

[0050] As Figure 5As shown in the figure, fuzzy control is introduced into the voltage loop ADRC of the DC-DC converter system, and the fuzzy controller adopted is a single-variable two-dimensional fuzzy controller. The difference between the actual voltage and the given voltage is used as the voltage error e, and the voltage error e and the error change rate ec are used as the two input variables of the fuzzy controller. The correction values △K2, △K31, △K32, etc. of the parameters to be tuned in ADRC are used as the output variables, realizing the real-time tuning and optimization of the ADRC parameters based on fuzzy control.

[0051] Furthermore, the current loop Fuzzy-PID control structure for constructing the output current of the Buck circuit includes:

[0052] A second fuzzy controller and a PID controller are established. The current error is used as the input variable of the second fuzzy controller, and the kp, ki, and kd of the PID controller are used as the output variables, so that the duty cycle of the PWM wave output by the PID controller generates a corresponding PWM drive signal as the error between the output and the given voltage changes.

[0053] In practical applications, the Fuzzy-PID control structure is used for the PWM waveform of the control signal of the Buck circuit of the DC-DC converter. The second fuzzy controller fuzzily controls the control parameters of the PID controller, so that the PID controller generates a corresponding PWM drive signal as the error between the output and the given voltage changes, to precisely control the conduction and cut-off of the switching tube of the Buck circuit, thereby achieving the best control effect.

[0054] Furthermore, an ADRC controller is established, including:

[0055] The mathematical models corresponding to the tracking differentiator TD, the nonlinear state error feedback NLSEF, and the extended state observer ESO are established. The uncertainties and internal and external disturbances are regarded as the total disturbances of the system, and the total disturbances are estimated and compensated through the nonlinear state error feedback NLSEF and the extended state observer ESO.

[0056] Specifically, as Figure 4 shown, ADRC not only does not depend on the accurate model of the controlled object like the classical PID control, but also solves the problem that rapidity and overshoot cannot be both achieved in PID control. The core idea of ADRC is to regard the uncertainties and internal and external disturbances of the system as the total disturbances of the system, and through the ESO and NLSEF, the real-time and accurate estimation and compensation of the total disturbances of the system are realized, so as to simplify the control object full of uncertainties and disturbances into a standard integral series type for control, which is beneficial to improving the stability, anti-interference ability, and robustness of the system.

[0057] Furthermore, both the first fuzzy controller and the second fuzzy controller are single-variable two-dimensional fuzzy controllers.

[0058] In practical applications, the first fuzzy controller and the second fuzzy controller formulate a rule base or a knowledge base according to the test results to automatically perform fuzzy control on the corresponding ADRC parameters and PID parameters, so as to achieve the auto-disturbance rejection control of ADRC and the generation of PWM drive signals.

[0059] It can be seen that the present invention provides a method for controlling the output of a DC-DC converter for a new energy vehicle. A voltage-loop Fuzzy-ADRC control structure is constructed based on a Buck circuit to improve the dynamic response and anti-disturbance ability of the system. At the same time, a current-loop Fuzzy-PID control structure is constructed to generate corresponding PWM drive signals to accurately control the conduction and turn-off of the switching tubes of the Buck circuit, thereby ensuring the stability and efficiency of the entire system. It solves the problem that the output voltage of the existing DC-DC converter for a new energy vehicle is difficult to stabilize when supplying power to low-voltage components, can improve the stability, response speed and voltage output accuracy of the DC-DC converter system for a new energy vehicle, and reduce the energy consumption of the whole vehicle.

[0060] Correspondingly, as Figure 2 shown, the present invention also provides an output control system for a DC-DC converter of a new energy vehicle, which uses the above control method and includes: a Buck circuit module, a voltage signal acquisition module and a Fuzzy-ADRC controller. The input end of the voltage signal acquisition module is connected to the output end of the Buck circuit module, and the output end of the voltage signal acquisition module is connected to the input end of the Fuzzy-ADRC controller to construct a voltage-loop Fuzzy-ADRC control structure, so that the Fuzzy-ADRC controller can accurately estimate and compensate the total disturbance of the output current of the Buck circuit in real time.

[0061] In practical applications, the voltage signal acquisition module is used to collect the output voltage of the Buck circuit module in real time, compare the collected actual output voltage with the set voltage to obtain the voltage error and the rate of change of the voltage error, and then use the voltage error and the rate of change of the voltage error as input variables to input into the Fuzzy-ADRC controller for fuzzy auto-disturbance rejection control. The AD7606 chip can be used for the voltage signal acquisition module.

[0062] The system further includes: a Fuzzy-PID controller and a PWM drive module; the input end of the PWM drive module is connected to the output end of the Fuzzy-PID controller, and the output end of the PWM drive module is connected to the control end of the switching power supply of the Buck circuit to construct a current-loop Fuzzy-ADRC control structure, so that the Fuzzy-PID controller generates corresponding PWM drive signals according to the current error between the actual output current of the Buck circuit and the compensated reference current.

[0063] The system further includes: a current acquisition module; the input end of the current acquisition module is connected to the output end of the Buck circuit module, the output end of the current acquisition module is connected to the input end of the Fuzzy-PID controller, and the current acquisition module collects the actual output current of the Buck circuit in real time. The input end of the Fuzzy-PID controller is further connected to the output end of the Fuzzy-ADRC controller.

[0064] In practical applications, the current acquisition module is used to collect the output current of the Buck circuit module in real time, and compare the collected actual output current with the reference current output by the Fuzzy-ADRC controller to obtain the current error and the rate of change of the current error, and use them as the input variables of the Fuzzy-PID controller, so that the Fuzzy-PID generates corresponding PWM drive signals when the load changes and the input voltage fluctuates, so as to accurately control the conduction and turn-off of the switching tube of the Buck circuit. The current acquisition module can use the ADS1256 chip.

[0065] Furthermore, the PWM drive module is a PWM wave generator.

[0066] In practical applications, the PWM wave generator can use the SG3525 chip.

[0067] It can be seen that the present invention provides an output control system for a new energy vehicle DC-DC converter, which constructs a voltage loop Fuzzy-ADRC control structure based on the Buck circuit to improve the dynamic response and anti-disturbance ability of the system, and at the same time constructs a current loop Fuzzy-PID control structure to generate corresponding PWM drive signals to accurately control the conduction and turn-off of the switching tube of the Buck circuit, thereby ensuring the stability and efficiency of the entire system. It solves the problem that the output voltage of the existing new energy vehicle DC-DC converter is difficult to stabilize when supplying power to low-voltage components, and can improve the stability, response speed and voltage output accuracy of the new energy vehicle DC-DC converter system, and reduce the energy consumption of the whole vehicle.

[0068] The above has detailed the structure, features and effects of the present invention according to the illustrated embodiments. The above is only the preferred embodiment of the present invention, but the present invention is not limited to the scope defined by the drawings. Any changes made according to the concept of the present invention, or equivalent embodiments modified into equivalent changes, still fall within the spirit covered by the specification and the drawings, and should be within the protection scope of the present invention.

Claims

1. A method for controlling the output of a DC-DC converter in a new energy vehicle, characterized in that, Including: Obtain the output voltage of the Buck circuit, and compare the output voltage with a set voltage to obtain a voltage error and an error change rate; Establish a voltage-loop Fuzzy-ADRC control structure for the output voltage of the Buck circuit to perform fuzzy control and active disturbance rejection control on the output voltage of the Buck circuit; The voltage-loop Fuzzy-ADRC control structure estimates and compensates the total disturbance of the output current of the Buck circuit in real time and accurately according to the voltage error and the error change rate.

2. The output control method of the DC-DC converter for new energy vehicles according to claim 1, characterized in that Also including: Construct a current-loop Fuzzy-PID control structure for the output current of the Buck circuit to generate a corresponding PWM drive signal according to the current error between the actual output current of the Buck circuit and the compensated reference current; Precisely control the conduction or cutoff of the switching tube of the Buck circuit according to the PWM drive signal, so that the Buck circuit can respond quickly and maintain the stability of the output voltage in the face of load changes and input voltage fluctuations.

3. The output control method of the DC-DC converter for new energy vehicles according to claim 2, wherein, The establishment of the voltage-loop Fuzzy-ADRC control structure for the output voltage of the Buck circuit includes: Establish a first fuzzy controller and an ADRC controller, use the voltage error and the error change rate as two input variables of the first fuzzy controller, and use the correction value of the parameter to be tuned in the ADRC controller as the output variable, so that the fuzzy controller can perform real-time tuning and optimization on the ADRC parameters of the ADRC controller.

4. The output control method of the DC-DC converter for new energy vehicles according to claim 3, wherein The construction of the current-loop Fuzzy-PID control structure for the output current of the Buck circuit includes: Establish a second fuzzy controller and a PID controller, use the current error as the input variable of the second fuzzy controller, and use the kp, ki, and kd of the PID controller as the output variables, so that the duty cycle of the PWM wave output by the PID controller generates a corresponding PWM drive signal as the error between the output and the given voltage changes.

5. The output control method of the DC-DC converter for new energy vehicles according to claim 4, characterized in that The establishment of the ADRC controller includes: Establish the mathematical models corresponding to the tracking differentiator TD, the nonlinear state error feedback NLSEF, and the extended state observer ESO, regard the uncertainty and internal and external disturbances as the total disturbance of the system, and estimate and compensate the total disturbance through the nonlinear state error feedback NLSEF and the extended state observer ESO.

6. The output control method of the DC-DC converter for new energy vehicles according to claim 5, characterized in that, Both the first fuzzy controller and the second fuzzy controller are single-variable two-dimensional fuzzy controllers.

7. An output control system for a DC-DC converter of a new energy vehicle, using the control method according to any one of claims 1 to 6, characterized in that, Including: Buck circuit module, voltage signal acquisition module, and Fuzzy-ADRC controller; The input end of the voltage signal acquisition module is connected to the output end of the Buck circuit module, and the output end of the voltage signal acquisition module is connected to the input end of the Fuzzy-ADRC controller to construct a voltage-loop Fuzzy-ADRC control structure, so that the Fuzzy-ADRC controller estimates and compensates the total disturbance of the output current of the Buck circuit in real time and accurately.

8. The output control system of the DC-DC converter for new energy vehicles according to claim 7, wherein, Also including: Fuzzy-PID controller and PWM drive module; The input end of the PWM driving module is connected to the output end of the Fuzzy-PID controller, and the output end of the PWM driving module is connected to the control end of the switching power supply of the Buck circuit, so as to construct a current-loop Fuzzy-ADRC control structure, and enable the Fuzzy-PID controller to generate a corresponding PWM driving signal according to the current error between the actual output current of the Buck circuit and the compensated reference current.

9. The output control system of the DC-DC converter for new energy vehicles according to claim 8, wherein, It further includes: A current acquisition module; The input end of the current acquisition module is connected to the output end of the Buck circuit module, and the output end of the current acquisition module is connected to the input end of the Fuzzy-PID controller. The current acquisition module real-time acquires the actual output current of the Buck circuit; The input end of the Fuzzy-PID controller is further connected to the output end of the Fuzzy-ADRC controller.

10. The output control system of the DC-DC converter for a new energy vehicle according to claim 9, wherein The PWM driving module is a PWM wave generator.

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