Vehicle-mounted MPPT photovoltaic charging method

Abstract

The invention discloses a vehicle-mounted MPPT (maximum power point tracking) photovoltaic charging method, which relates to the technical field of vehicle-mounted photovoltaic charging and comprises the following steps: constructing a Buck-Boost circuit topology, acquiring an analog output signal of a vehicle-mounted photovoltaic module in real time through a sampling circuit, and converting the analog output signal into a corresponding digital signal; the obtained digital signals are analyzed, and whether a protection program is executed or not is judged according to the analysis result; simulating the output power of the vehicle-mounted photovoltaic module based on an MPPT algorithm so as to obtain corresponding reference voltage and reference current; the actual output of the vehicle-mounted photovoltaic module is compared with the reference voltage and the reference current, the actual output of the vehicle-mounted photovoltaic module is compensated according to the obtained error value, and then a corresponding PWM signal is generated; and adjusting the direct current output by the vehicle-mounted photovoltaic module according to the PWM signal, and collecting the output to a direct current bus to complete the charging of the battery.

Description

Technical Field

[0001] This invention relates to the field of vehicle-mounted photovoltaic charging technology, specifically a vehicle-mounted MPPT photovoltaic charging method. Background Technology

[0002] With increasing global focus on clean energy and sustainable development, photovoltaic power generation, as an important renewable energy source, is seeing its application scope continuously expand, especially in the fields of mobile power and vehicle auxiliary power supply. In actual vehicle environments, photovoltaic modules often face complex operating conditions such as uneven illumination and partial shading. Traditional single-path maximum power point tracking (MPPT) systems are difficult to effectively cope with the differences between multiple photovoltaic modules, resulting in a decrease in overall power generation efficiency. Therefore, an on-board MPPT photovoltaic charging method is provided. Summary of the Invention

[0003] The purpose of this invention is to provide an on-board MPPT photovoltaic charging method.

[0004] The objective of this invention can be achieved through the following technical solution: an on-board MPPT photovoltaic charging method, comprising: Construct a Buck-Boost circuit topology to enable controllable voltage regulation of the switch; The analog output signal of the vehicle-mounted photovoltaic module is collected in real time by the sampling circuit, and the collected analog output signal is converted into the corresponding digital signal. The obtained digital signals are analyzed, and the results are used to determine whether to execute the protection procedure. The output power of the vehicle-mounted photovoltaic module is simulated based on the MPPT algorithm, and then the corresponding reference voltage and reference current are obtained. The actual output of the vehicle-mounted photovoltaic module is compared with the reference voltage and reference current. The corresponding error value is obtained based on the comparison results, and then the actual output of the vehicle-mounted photovoltaic module is compensated based on the obtained error value. The duty cycle of the Buck-Boost converter is adjusted according to the compensated error value, thereby generating the corresponding PWM signal; The DC power output from the vehicle-mounted photovoltaic module is regulated according to the PWM signal, and the output is collected to the DC bus to complete the charging of the battery.

[0005] Furthermore, a Buck-Boost circuit topology is constructed to allow for controllable voltage adjustment of the switches, including: Construct a Buck-Boost circuit topology for controllable output adjustment; The Buck-Boost circuit topology includes an inductor, a MOSFET, a freewheeling diode, a sampling circuit, and an output filter.

[0006] Furthermore, the Buck-Boost circuit topology incorporates two MOSFETs.

[0007] Furthermore, the process of acquiring the analog output signal of the vehicle-mounted photovoltaic module in real time through the sampling circuit and converting the acquired analog output signal into the corresponding digital signal includes: The output current and output voltage of the vehicle photovoltaic module are sampled by the sampling circuit in the Buck-Boost circuit topology to obtain the corresponding analog output signal, which includes analog current output signal and analog voltage output signal. The analog power output signal of the corresponding vehicle-mounted photovoltaic module is obtained based on the obtained analog current output signal and analog voltage output signal; The obtained analog signals are then conditioned and converted from analog to digital to digital signals.

[0008] Furthermore, the process of analyzing the acquired digital signal and determining whether to execute the protection procedure based on the analysis results includes: Set the output voltage threshold, output current threshold, battery voltage threshold, battery current threshold, and temperature threshold respectively; When any one of the following conditions is met: the output voltage of the vehicle photovoltaic module exceeds the output voltage threshold, the output current of the vehicle photovoltaic module exceeds the output current threshold, the voltage of the vehicle battery exceeds the battery voltage threshold, the current of the vehicle battery exceeds the battery current threshold, or the temperature of the radiator exceeds the temperature threshold, the protection program will be activated, and shutdown and wave blocking protection will be performed according to the protection program, and an alarm will be triggered.

[0009] Furthermore, the process of simulating the output power of the vehicle-mounted photovoltaic module based on the MPPT algorithm to obtain the corresponding reference voltage and reference current includes: Set a perturbation step size for the output voltage and output current of the Buck-Boost circuit topology, and perturb the output voltage and output current of the Buck-Boost circuit topology according to the set perturbation step size; When a perturbation step size is increased, the corresponding output voltage and output current are resampled, and the corresponding analog power output signal is recalculated to obtain the power change before and after the perturbation. If the power increases, the duty cycle of the Buck-Boost converter is increased; if the power decreases, the duty cycle of the Buck-Boost converter is decreased, until the optimal output voltage and output current are found, denoted as the reference voltage and reference current.

[0010] Furthermore, the actual output of the vehicle-mounted photovoltaic module is compared with the reference voltage and reference current. Based on the comparison results, the corresponding error value is obtained, and a corresponding error signal is generated. The actual output of the vehicle-mounted photovoltaic module is then compensated based on the generated error signal.

[0011] Furthermore, the process of regulating the DC power output from the on-board photovoltaic modules according to the PWM signal and then converging the output to the DC bus to complete the charging of the battery includes: The generated PWM signal is converted into a corresponding gate drive signal to control the MOSFET in the Buck-Boost converter. The Buck-Boost circuit topology converts the DC power input from the vehicle photovoltaic module to the vehicle battery into either a boost or a buck voltage based on the received PWM signal. When the voltage of the vehicle's photovoltaic module is higher than the voltage of the DC bus, the Buck-Boost circuit topology performs buck mode (Buck) on the current input from the vehicle's photovoltaic module to the vehicle's battery. When the voltage of the photovoltaic module is lower than the voltage of the DC bus, the Buck-Boost circuit topology performs boost mode (Boost) on the current input from the vehicle's photovoltaic module to the vehicle's battery. When the voltage of the vehicle's photovoltaic module is the same as the voltage of the DC bus, no operation is performed.

[0012] Compared with the prior art, the present invention has the following beneficial effects: By employing four independent MPPT and Buck-Boost circuits, the efficiency reduction caused by uneven lighting in the vehicle environment is effectively solved, maximizing the extraction of energy from photovoltaic modules and significantly improving the overall photovoltaic energy utilization efficiency. Attached Figure Description

[0013] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments described in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0014] Figure 1 This is a flowchart of the present invention; Figure 2 This is a schematic diagram of the Buck-Boost circuit topology of the present invention. Detailed Implementation

[0015] like Figure 1 As shown, an on-board MPPT photovoltaic charging method includes: Construct a Buck-Boost circuit topology to enable controllable voltage regulation of the switch; The analog output signal of the vehicle-mounted photovoltaic module is collected in real time by the sampling circuit, and the collected analog output signal is converted into the corresponding digital signal. The obtained digital signals are analyzed, and the results are used to determine whether to execute the protection procedure. The output power of the vehicle-mounted photovoltaic module is simulated based on the MPPT algorithm, and then the corresponding reference voltage and reference current are obtained. The actual output of the vehicle-mounted photovoltaic module is compared with the reference voltage and reference current. The corresponding error value is obtained based on the comparison results, and then the actual output of the vehicle-mounted photovoltaic module is compensated based on the obtained error value. The duty cycle of the Buck-Boost converter is adjusted according to the compensated error value, thereby generating the corresponding PWM signal; The DC power output from the vehicle-mounted photovoltaic module is regulated according to the PWM signal, and the output is collected to the DC bus to complete the charging of the battery.

[0016] It should be further explained that, in the specific implementation process, the input starting voltage range of the vehicle photovoltaic module is 25V to 80V, and the working voltage range of the vehicle battery is 48V to 56V. Therefore, it is necessary to adjust the output of the vehicle photovoltaic module. In another embodiment of the invention, such as Figure 2 As shown: Constructing a Buck-Boost circuit topology for controllable voltage adjustment of the switches includes: Construct a Buck-Boost circuit topology for controllable output adjustment; The Buck-Boost circuit topology includes an inductor, a MOSFET, a freewheeling diode, a sampling circuit, and an output filter. It should be noted that this invention improves the current carrying capacity of the Buck-Boost circuit topology, reduces conduction and switching losses, and improves heat distribution and reliability by setting two MOSFETs in the Buck-Boost circuit topology.

[0017] In another embodiment of the present invention, the process of acquiring the analog output signal of the vehicle-mounted photovoltaic module in real time through a sampling circuit and converting the acquired analog output signal into a corresponding digital signal includes: The output current and output voltage of the vehicle photovoltaic module are sampled by the sampling circuit in the Buck-Boost circuit topology to obtain the corresponding analog output signal, which includes analog current output signal and analog voltage output signal. The analog current output signal is denoted as Ipv, and the analog voltage output signal is denoted as Vpv; Based on the obtained analog current output signal and analog voltage output signal, the corresponding analog power output signal of the vehicle-mounted photovoltaic module is obtained, denoted as Ppv, where: Ppv = Ipv × Vpv; The obtained analog signals are then conditioned and converted into digital signals by analog-to-digital conversion (ADC).

[0018] In another embodiment of the present invention, the process of analyzing the obtained digital signal and determining whether to execute the protection procedure based on the analysis result includes: Set the output voltage threshold, output current threshold, battery voltage threshold, battery current threshold, and temperature threshold respectively; When any one of the following conditions is met: the output voltage of the vehicle photovoltaic module exceeds the output voltage threshold, the output current of the vehicle photovoltaic module exceeds the output current threshold, the voltage of the vehicle battery exceeds the battery voltage threshold, the current of the vehicle battery exceeds the battery current threshold, or the temperature of the radiator exceeds the temperature threshold, the protection program will be activated, and shutdown and wave blocking protection will be performed according to the protection program, and an alarm will be triggered.

[0019] In another embodiment of the present invention, the process of simulating the output power of the vehicle-mounted photovoltaic module based on the MPPT algorithm to obtain the corresponding reference voltage and reference current includes: Set a perturbation step size for the output voltage and output current of the Buck-Boost circuit topology, and perturb the output voltage and output current of the Buck-Boost circuit topology according to the set perturbation step size; When a perturbation step size is increased, the corresponding output voltage and output current are resampled, and the corresponding analog power output signal is recalculated to obtain the power change before and after the perturbation. If the power increases, the duty cycle of the Buck-Boost converter is increased; if the power decreases, the duty cycle of the Buck-Boost converter is decreased, until the optimal output voltage and output current are found, denoted as the reference voltage and reference current.

[0020] In another embodiment of the present invention, the actual output of the vehicle-mounted photovoltaic module is compared with a reference voltage and a reference current, and the corresponding error value is obtained based on the comparison result, and a corresponding error signal is generated. The actual output of the vehicle-mounted photovoltaic module is compensated based on the generated error signal.

[0021] In another embodiment of the present invention, the process of adjusting the DC power output of the vehicle-mounted photovoltaic module according to the PWM signal and collecting the output to the DC bus to complete the charging of the battery includes: The generated PWM signal is converted into a corresponding gate drive signal to control the MOSFET in the Buck-Boost converter. The Buck-Boost circuit topology converts the DC power input from the vehicle photovoltaic module to the vehicle battery into either a boost or a buck voltage based on the received PWM signal. When the voltage of the vehicle photovoltaic module is higher than the voltage of the DC bus, the Buck-Boost circuit topology performs buck mode (Buck) on the current input from the vehicle photovoltaic module to the vehicle battery. When the voltage of the photovoltaic module is lower than the voltage of the DC bus, the Buck-Boost circuit topology performs boost mode (Boost) on the current input from the vehicle photovoltaic module to the vehicle battery. When the voltage of the vehicle photovoltaic module is the same as the voltage of the DC bus, no operation is performed. By precisely controlling the duty cycle, the Buck-Boost converter can adjust the output voltage and current of the photovoltaic module to the optimal operating point determined by the MPPT algorithm and efficiently transfer energy to the DC bus.

[0022] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any modifications or equivalent substitutions made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A vehicle-mounted MPPT photovoltaic charging method, characterized in that, include: Construct a Buck-Boost circuit topology to enable controllable voltage regulation of the switch; The analog output signal of the vehicle-mounted photovoltaic module is collected in real time by the sampling circuit, and the collected analog output signal is converted into the corresponding digital signal. The obtained digital signals are analyzed, and the results are used to determine whether to execute the protection procedure. The output power of the vehicle-mounted photovoltaic module is simulated based on the MPPT algorithm, and then the corresponding reference voltage and reference current are obtained. The actual output of the vehicle-mounted photovoltaic module is compared with the reference voltage and reference current. The corresponding error value is obtained based on the comparison results, and then the actual output of the vehicle-mounted photovoltaic module is compensated based on the obtained error value. The duty cycle of the Buck-Boost converter is adjusted according to the compensated error value, thereby generating the corresponding PWM signal; The DC power output from the vehicle-mounted photovoltaic module is regulated according to the PWM signal, and the output is collected to the DC bus to complete the charging of the battery.

2. The vehicle-mounted MPPT photovoltaic charging method according to claim 1, characterized in that, Constructing a Buck-Boost circuit topology for controllable voltage adjustment of the switches includes: Construct a Buck-Boost circuit topology for controllable output adjustment; The Buck-Boost circuit topology includes an inductor, a MOSFET, a freewheeling diode, a sampling circuit, and an output filter.

3. The vehicle-mounted MPPT photovoltaic charging method according to claim 2, characterized in that, The Buck-Boost circuit topology incorporates two MOSFETs.

4. The vehicle-mounted MPPT photovoltaic charging method according to claim 3, characterized in that, The process of acquiring the analog output signal of the vehicle-mounted photovoltaic module in real time through a sampling circuit and converting the acquired analog output signal into the corresponding digital signal includes: The output current and output voltage of the vehicle photovoltaic module are sampled by the sampling circuit in the Buck-Boost circuit topology to obtain the corresponding analog output signal, which includes analog current output signal and analog voltage output signal. The analog power output signal of the corresponding vehicle-mounted photovoltaic module is obtained based on the obtained analog current output signal and analog voltage output signal; The obtained analog signals are then conditioned and converted from analog to digital to digital signals.

5. The vehicle-mounted MPPT photovoltaic charging method according to claim 4, characterized in that, The process of analyzing the acquired digital signal and determining whether to execute the protection procedure based on the analysis results includes: Set the output voltage threshold, output current threshold, battery voltage threshold, battery current threshold, and temperature threshold respectively; When any one of the following conditions is met: the output voltage of the vehicle photovoltaic module exceeds the output voltage threshold, the output current of the vehicle photovoltaic module exceeds the output current threshold, the voltage of the vehicle battery exceeds the battery voltage threshold, the current of the vehicle battery exceeds the battery current threshold, or the temperature of the radiator exceeds the temperature threshold, the protection program will be activated, and shutdown and wave blocking protection will be performed according to the protection program, and an alarm will be triggered.

6. The vehicle-mounted MPPT photovoltaic charging method according to claim 5, characterized in that, The process of simulating the output power of vehicle-mounted photovoltaic modules based on the MPPT algorithm, and then obtaining the corresponding reference voltage and reference current, includes: Set a perturbation step size for the output voltage and output current of the Buck-Boost circuit topology, and perturb the output voltage and output current of the Buck-Boost circuit topology according to the set perturbation step size; When a perturbation step size is increased, the corresponding output voltage and output current are resampled, and the corresponding analog power output signal is recalculated to obtain the power change before and after the perturbation. If the power increases, the duty cycle of the Buck-Boost converter is increased; if the power decreases, the duty cycle of the Buck-Boost converter is decreased, until the optimal output voltage and output current are found, denoted as the reference voltage and reference current.

7. The vehicle-mounted MPPT photovoltaic charging method according to claim 6, characterized in that, The actual output of the vehicle-mounted photovoltaic module is compared with the reference voltage and reference current. The corresponding error value is obtained based on the comparison result, and the corresponding error signal is generated. The actual output of the vehicle-mounted photovoltaic module is compensated based on the generated error signal.

8. The vehicle-mounted MPPT photovoltaic charging method according to claim 7, characterized in that, The process of regulating the DC power output from the vehicle-mounted photovoltaic modules based on the PWM signal and then converging the output to the DC bus to complete the charging of the battery includes: The generated PWM signal is converted into a corresponding gate drive signal to control the MOSFET in the Buck-Boost converter. The Buck-Boost circuit topology converts the DC power input from the vehicle photovoltaic module to the vehicle battery into either a boost or a buck voltage based on the received PWM signal. When the voltage of the vehicle photovoltaic module is higher than the voltage of the DC bus, the Buck-Boost circuit topology performs a step-down mode on the current input from the vehicle photovoltaic module to the vehicle battery. When the voltage of the photovoltaic module is lower than the voltage of the DC bus, the Buck-Boost circuit topology performs a step-up mode on the current input from the vehicle photovoltaic module to the vehicle battery. When the voltage of the vehicle photovoltaic module is the same as the voltage of the DC bus, no operation is performed.

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