PID (Proportion Integration Differentiation) control-based high-frequency pulse active energy acquisition microbial electrochemical system and method

Abstract

The invention discloses a high-frequency pulse active energy acquisition microbial electrochemical system and method based on PID control. The system comprises an MES, an energy management module, a first signal acquisition module, a second signal acquisition module, an A / D conversion module, an energy storage module and a control module, wherein the input of the energy management module is connected with the output of the MES, and the output of the energy management module is connected with the input of the energy storage module; the input of the first signal acquisition module is respectively connected in parallel with the output of the MES and the sampling resistor R1, and the output of the first signal acquisition module is connected with the input of the A / D conversion module; the input of the second signal acquisition module is respectively connected in parallel with the input of the energy storage module and the sampling resistor R2, and the output of the second signal acquisition module is connected with the input of the A / D conversion module; the A / D conversion module is interconnected with the control module through a data communication line, and the output of the A / D conversion module is connected with the input of the energy management module.

Description

Technical Field

[0001] The present invention belongs to the field of microbial battery power generation, and in particular relates to a high-frequency pulsation active energy harvesting microbial electrochemical system and method based on PID control. Background Art

[0002] Microbial electrochemical system (MES), as a technology for organic pollutant treatment and sustainable energy regeneration, combines the advantages of microbial cascade degradation of organic matter with efficient electrochemical catalysis. It has become an emerging technology with great research prospects for organic pollutant degradation and energy regeneration in the environmental field, and has broad scientific research value and application prospects.

[0003] In MES, microorganisms on the electrode surface oxidize the electron donors in organic matter and transfer the electrons to the anode. The generated electrons migrate through the external circuit and ultimately reach the cathode. Through the release, transfer, and electrochemical reaction of electrons, organic pollutants can be bioconverted and bioenergy (bioelectricity, hydrogen, or methane) can be regenerated. Electrochemical synthesis processes can also be carried out at the cathode to produce small volatile acids.

[0004] As MES functionality continues to expand, amplifying and improving power output is a pressing challenge to drive its development. To maintain maximum power generation, the system should operate at maximum power. However, the vast majority of current MES use external resistors or capacitors to passively collect electrons from the anode, relying entirely on the microbial power generation process to generate electricity, with little control over the system. Furthermore, the internal resistance and power generation efficiency of the MES change in real time with factors such as the microbial growth cycle, external temperature, pH, and substrate concentration, causing the generated current to constantly fluctuate, making it virtually impossible to apply directly. Existing active energy harvesting methods are susceptible to interference from external environmental conditions and are unable to accurately track the current maximum power point. Furthermore, tracking accuracy and tracking speed are mutually constrained, resulting in significant efficiency losses. Summary of the Invention

[0005] To solve the above technical problems, the present invention proposes a high-frequency pulsation active energy harvesting microbial electrochemical system and method based on PID control, which can extract or stop the transmission of circuit electrons in real time under different environmental conditions, thereby enhancing extracellular electron transfer and greatly improving the power collection efficiency, energy efficiency and wastewater treatment capacity of the MES.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A high-frequency pulsation active energy harvesting microbial electrochemical system based on PID control comprises: an MES, an energy management module, a first signal acquisition module, a second signal acquisition module, an A / D conversion module, an energy storage module and a control module; wherein, the input of the energy management module is connected to the output of the MES, and the output of the energy management module is connected to the input of the energy storage module; the input of the first signal acquisition module is respectively connected in parallel with the output of the MES and a sampling resistor R1, and the output of the first signal acquisition module is connected to the input of the A / D conversion module; the input of the second signal acquisition module is respectively connected in parallel with the input of the energy storage module and a sampling resistor R2, and the output of the second signal acquisition module is connected to the input of the A / D conversion module; the A / D conversion module and the control module are interconnected via a data communication line, and the output of the A / D conversion module is connected to the input of the energy management module.

[0008] Optionally, the MES utilizes electroactive microorganisms as biocatalysts to convert chemical energy into electrical energy and other bioproducts.

[0009] Optionally, the energy management module adopts an ultra-low power consumption pulse frequency modulation high-efficiency DC-DC boost converter, and adjusts the output voltage of the MES by adjusting the switching frequency of the DC-DC boost converter to change the equivalent load of the MES.

[0010] Optionally, the first signal acquisition module is used to collect the output current and voltage of the MES in real time, and monitor the working status of the MES in real time based on the output current and voltage of the MES;

[0011] Optionally, the second signal acquisition module is used to collect the charging current and voltage of the energy storage module in real time, and monitor the working status of the energy storage module in real time based on the charging current and voltage of the energy storage module.

[0012] Optionally, the A / D conversion module is used to convert the analog output quantities of the first signal acquisition module and the second signal acquisition module into digital quantities, and input them into the control module through data communication. It can also convert the maximum power point voltage value output by the control module into an analog quantity and transmit it to the energy management module.

[0013] Optionally, the energy storage module is used to store the bioelectricity collected by the energy management module.

[0014] Optionally, the control module is used to receive the MES working status data transmitted by the A / D conversion module, and use the A / D conversion module to convert the calculated current maximum power point voltage of the MES into an analog quantity and output it to the energy management module, so that the MES operates at the maximum power point state.

[0015] The present invention also provides a microbial electrochemical method for high-frequency pulsation active energy harvesting based on PID control, comprising:

[0016] S1, obtaining a reference voltage according to the A / D conversion module, and adjusting the output voltage of the MES to the reference voltage;

[0017] S2. Using the first signal acquisition module and the second signal acquisition module to collect the output voltage of the MES, the voltage across the sampling resistor R1, the input voltage U3 of the energy storage module, and the voltage across the sampling resistor R2 in real time, and based on the collected data, using the control module to calculate the average value of the collected voltages, obtain the current output voltage, output current, and output power of the MES, and subtract them from the output power and output voltage sampled values ​​of the previous cycle to obtain an output power difference ΔP(k) and an output voltage difference ΔU(k);

[0018] S3, determining whether the voltage difference ΔU(k) ​​is less than a threshold value. If the voltage difference ΔU(k) ​​is less than the threshold value, assigning a value to the voltage difference; otherwise, executing S4;

[0019] S4. Determine the sign of the ratio of the power difference ΔP(k) to the voltage difference ΔU(k). If If the current operating point is to the left of the maximum power point, the voltage needs to be increased and the reference voltage needs to be updated; otherwise, if the current operating point is to the right of the maximum power point, the voltage needs to be decreased and the reference voltage needs to be updated;

[0020] S5. Repeat steps S2 to S4 until the MES operating point reaches the maximum power point.

[0021] Optionally, the method for updating the reference voltage is:

[0022]

[0023] Among them, V ref (k) is the updated reference voltage, V ref (k-1) is the reference voltage of the previous cycle, K pi Different proportional coefficients are introduced according to the symbols to achieve adaptive adjustment of step size.

[0024] Compared with the prior art, the present invention has the following advantages and technical effects:

[0025] 1. This invention utilizes high-frequency pulsed energy harvesting technology, based on an optimized adaptive maximum power point tracking strategy, to maintain efficient microbial operation under varying environmental conditions, ensuring that the MES consistently operates at its maximum power point. This novel energy harvesting approach significantly improves the MES's power and energy efficiency, as well as its wastewater treatment capacity.

[0026] 2. This invention achieves high energy efficiency in active energy harvesting hardware systems, enabling self-controlled energy collection without the need for external power supply. The recovered energy can also be used to operate other bioreactors. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of this application. The exemplary embodiments and descriptions of this application are intended to explain this application and do not constitute an improper limitation on this application. In the accompanying drawings:

[0028] Figure 1 This is a schematic diagram of the operation of a multi-anode MES energy harvesting system according to an embodiment of the present invention;

[0029] Figure 2 This is a structural functional block diagram of a high-frequency pulsation active energy harvesting microbial electrochemical system based on PID control according to an embodiment of the present invention;

[0030] Figure 3 1 is a schematic diagram of the MES output PU curve and its derivative curve according to an embodiment of the present invention;

[0031] Figure 4 This is a mathematical model diagram of a method for implementing high-frequency pulsation maximum power point tracking based on PID control according to an embodiment of the present invention;

[0032] Figure 5 This is a flow chart of a high-frequency pulsation active energy harvesting method based on PID control according to an embodiment of the present invention. DETAILED DESCRIPTION

[0033] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0034] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer or microcontroller that can execute instructions, and although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0035] This embodiment proposes a high-frequency pulsation active energy harvesting microbial electrochemical system based on PID control, and its operation schematic diagram and structural principle diagram are shown in FIG. Figure 1 and Figure 2 As shown, it includes: MES, energy management module, signal acquisition module 1 (first signal acquisition module), signal acquisition module 2 (second signal acquisition module), A / D conversion module, energy storage module and control module; the input of the energy management module is connected to the output of the MES, and the output of the energy management module is connected to the input of the energy storage module; the input of the signal acquisition module 1 is respectively connected in parallel with the output of the MES and the sampling resistor R1, and the output of the signal acquisition module 1 is connected to the input of the A / D conversion module; the input of the signal acquisition module 2 is respectively connected in parallel with the input of the energy storage module and the sampling resistor R2, and the output of the signal acquisition module 2 is connected to the input of the A / D conversion module; the A / D conversion module and the control module are interconnected through a data communication line, and the output of the A / D conversion module is connected to the input of the energy management module;

[0036] MES uses electroactive microorganisms as biocatalysts to convert chemical energy into electrical energy and other biological products; MES can be a microbial fuel cell, a microbial solar cell, etc.; MES can be a small or large-scale reactor, and its structure can be a monopolar reactor or a multipolar reactor or multiple monopolar reactors in series or parallel.

[0037] The energy management module is used for energy harvesting in the microwatt to milliwatt range, with an input voltage as low as 110mV, fully meeting the energy harvesting requirements of the MES. The energy management module utilizes an ultra-low-power, pulse-frequency modulated (PFM) high-efficiency DC-DC boost converter. By adjusting the switching frequency of the DC-DC boost converter, it changes the equivalent load of the MES, thereby adjusting the output voltage of the MES. The energy management module supports a programmable maximum power point tracking mode and can be combined with a complex custom maximum power point tracking algorithm to achieve more efficient active energy harvesting technology. The energy management module can utilize integrated intelligent power management integrated circuits such as the BQ25505 or BQ25570 from Texas Instruments.

[0038] Signal acquisition module 1 is used to collect the output current and voltage of the MES in real time for real-time monitoring of the MES's operating status. Signal acquisition module 2 is used to collect the charging current and voltage of the energy storage module in real time for real-time monitoring of the energy storage module's operating status. The voltage can be directly collected through the analog voltage input of the A / D conversion module. The current can be obtained by measuring the voltage across the series resistor in the circuit, or directly collected through the analog current input of the A / D conversion module.

[0039] The A / D conversion module is used to convert analog and digital quantities. It can convert the analog outputs of signal acquisition modules 1 and 2 into digital quantities and input them into the control module through data communication. It can also convert the maximum power point voltage output by the control module into analog quantities and transmit them to the energy management module. The A / D conversion module can use a single-chip microcomputer or a data acquisition card from companies such as National Instruments and Advantech.

[0040] The energy storage module is used to store the bioelectricity collected by the energy management module. It can use rechargeable batteries, thin-film batteries, supercapacitors, traditional capacitors, etc. When the voltage of the energy storage module reaches the saturation value, a new energy storage module needs to be replaced;

[0041] The control module is used to generate an optimized maximum power point tracking algorithm. This module receives the MES operating status data transmitted by the A / D conversion module, calculates the current maximum power point voltage of the MES, and then uses the A / D conversion module to convert this voltage into an analog quantity and output it to the energy management module as its reference voltage, thereby enabling the MES to operate at the maximum power point state. The control module is a computer or microcontroller that can execute instructions. The control module can be programmed in languages ​​such as Matlab, Python, or C / C++. The A / D conversion module and the control module can communicate via serial or parallel buses such as PCI, PCIE, and USB.

[0042] Specifically, such as Figure 2 As shown in the figure, the working principle of this example is as follows: the A / D conversion module collects the output current and voltage of the MES and the charging current and voltage of the energy storage module in real time, thereby monitoring the working status of the MES and the energy storage module in real time. At the same time, the A / D conversion module can convert the analog quantity into a digital quantity and input it into the control module through data communication. The control module uses the optimized maximum power point tracking strategy to calculate the current maximum power point voltage of the MES, and after the digital-to-analog conversion by the A / D conversion module, it is used as the reference voltage V ref Output to the energy management module, reference voltage V ref Essentially, it is the theoretical reference value of the maximum power point voltage preset by the system. In power supply systems with nonlinear PU characteristics such as MES, V ref The target output voltage of the DC-DC boost converter is determined, so that the MES can operate at the maximum power point using the pulse frequency modulation mechanism.

[0043] Specifically, the classic control algorithm, PID control, is widely used in industrial control. As a closed-loop control method based on negative feedback of deviations, it has a simple structure, high reliability, and can quickly and effectively eliminate system deviations.

[0044] Design of high-frequency pulsation active energy harvesting method based on PID control: The output PU curve and its derivative curve of MES under certain environmental conditions are as follows: Figure 3 As shown in the figure, we can see that the maximum power point of MES is the point where the derivative of the PU curve is zero, and this point is unique. In the working range, it is a monotonically decreasing function. The absolute value of is positively correlated with the distance between the current operating point and the maximum power point. The value is used as the feedback signal of the PID controller to seek This point is the maximum power point.

[0045] According to the current working point on the PU curve, the switching frequency of the DC-DC boost converter is continuously adjusted to change the output equivalent load of the MES, thereby adjusting its output voltage until Thus, the maximum power point tracking is achieved. The structural block diagram of high frequency pulsation maximum power point tracking based on PID control is as follows: Figure 4 As shown in Figure 2. R represents the resistance of the equivalent external load.

[0046] The flow chart of a high-frequency pulsation active energy harvesting microbial electrochemical method based on PID control according to an embodiment of the present invention is as follows: Figure 5 As shown, the specific steps include:

[0047] In step S1, the control module outputs an initial reference voltage to the energy management module through the A / D conversion module. The energy management module adjusts the switching frequency of the DC-DC boost converter according to the reference voltage value, changes the equivalent load of the MES, and thus adjusts the output voltage of the MES to the reference voltage value.

[0048] S2, MES runs for a certain period of time at a given reference voltage until it reaches a stable state to eliminate the transient effect of the MES output voltage. Signal acquisition module 1 and signal acquisition module 2 respectively collect the MES output voltage U1, the voltage U2 across the sampling resistor R1, the energy storage module input voltage U3, and the voltage U4 across the sampling resistor R2 in real time within a certain period of time at a fixed sampling frequency. Signal acquisition module 1 and signal acquisition module 2 transmit the collected data to the control module in real time through the A / D conversion module. The control module records and calculates the average value of the collected voltage to eliminate the transient effect of MES power generation, thereby obtaining the current output voltage of MES. Output current and output power And compared with the output power of the previous cycle and output voltage The sampled values ​​are subtracted to obtain the output power difference ΔP(k) and the output voltage difference ΔU(k). The input voltage and current of the energy storage module are monitored at the same time.

[0049] S3, in order to avoid oscillation near the maximum power point, the control module needs to determine whether the voltage difference ΔU(k) ​​is less than the threshold uu min If so, assign a value to ΔU(k) ​​so that Otherwise, execute S4.

[0050] S4, the control module needs to determine the ratio between the power difference and the output voltage difference The symbol of The current operating point is on the left side of the maximum power point, and the voltage needs to be increased. It is positively correlated with the distance between the current operating point and the maximum power point, and the proportional coefficient K can be introduced p1 To achieve adaptive step size adjustment, the new reference voltage is: Otherwise, the current operating point is to the right of the maximum power point and the voltage needs to be reduced. The proportional coefficient K can be introduced. p2 To achieve adaptive step size adjustment, the new reference voltage is: Afterwards, the control module outputs the new reference voltage to the energy management module through the A / D conversion module;

[0051] S5. Repeat steps S2 to S4 until the MES operating point approaches the maximum power point infinitely.

[0052] The above are merely preferred embodiments of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A high-frequency pulsation active energy harvesting microbial electrochemical system based on PID control, characterized in that: include: MES, energy management module, first signal acquisition module, second signal acquisition module, A / D conversion module, energy storage module and control module; wherein, the input of the energy management module is connected to the output of the MES, and the output of the energy management module is connected to the input of the energy storage module; the input of the first signal acquisition module is respectively connected in parallel with the output of the MES and the sampling resistor R1, and the output of the first signal acquisition module is connected to the input of the A / D conversion module; the input of the second signal acquisition module is respectively connected in parallel with the input of the energy storage module and the sampling resistor R2, and the output of the second signal acquisition module is connected to the input of the A / D conversion module; the A / D conversion module and the control module are interconnected through a data communication line, and the output of the A / D conversion module is connected to the input of the energy management module.

2. A high-frequency pulsation active energy harvesting microbial electrochemical system based on PID control according to claim 1, characterized in that: The MES utilizes electroactive microorganisms as biocatalysts to convert chemical energy into electrical energy and other bioproducts.

3. The high-frequency pulsation active energy harvesting microbial electrochemical system based on PID control according to claim 1 is characterized in that: The energy management module adopts an ultra-low power consumption pulse frequency modulation high-efficiency DC-DC boost converter, and adjusts the output voltage of the MES by adjusting the switching frequency of the DC-DC boost converter to change the equivalent load of the MES.

4. The high-frequency pulsation active energy harvesting microbial electrochemical system based on PID control according to claim 1 is characterized in that: The first signal acquisition module is used to collect the output current and voltage of the MES in real time, and monitor the working status of the MES in real time based on the output current and voltage of the MES.

5. The high-frequency pulsation active energy harvesting microbial electrochemical system based on PID control according to claim 1 is characterized in that: The second signal acquisition module is used to collect the charging current and voltage of the energy storage module in real time, and monitor the working status of the energy storage module in real time based on the charging current and voltage of the energy storage module.

6. The high-frequency pulsation active energy harvesting microbial electrochemical system based on PID control according to claim 1 is characterized in that: The A / D conversion module is used to convert the analog output of the first signal acquisition module and the second signal acquisition module into digital quantities, and input them into the control module through data communication. It can also convert the maximum power point voltage value output by the control module into an analog quantity and transmit it to the energy management module.

7. The high-frequency pulsation active energy harvesting microbial electrochemical system based on PID control according to claim 1 is characterized in that: The energy storage module is used to store the bioelectricity collected by the energy management module.

8. The high-frequency pulsation active energy harvesting microbial electrochemical system based on PID control according to claim 1 is characterized in that: The control module is used to receive the MES operating status data transmitted by the A / D conversion module, and use the A / D conversion module to convert the calculated current maximum power point voltage of the MES into an analog value and output it to the energy management module, so that the MES operates at the maximum power point state.

9. A method for realizing the high-frequency pulsation active energy harvesting microbial electrochemical system based on PID control according to any one of claims 1 to 8, characterized in that: include: S1, obtaining a reference voltage according to the A / D conversion module, and adjusting the output voltage of the MES to the reference voltage; S2. Using the first signal acquisition module and the second signal acquisition module to collect the output voltage of the MES, the voltage across the sampling resistor R1, the input voltage U3 of the energy storage module, and the voltage across the sampling resistor R2 in real time, and based on the collected data, using the control module to calculate the average value of the collected voltages, obtain the current output voltage, output current, and output power of the MES, and subtract them from the output power and output voltage sampled values ​​of the previous cycle to obtain the output power difference ΔP(k) and the output voltage difference ΔU(k). S3, determining whether the voltage difference ΔU(k) ​​is less than a threshold value. If the voltage difference ΔU(k) ​​is less than the threshold value, assigning a value to the voltage difference; otherwise, executing S4; S4. Determine the sign of the ratio of the power difference ΔP(k) to the voltage difference ΔU(k). If If the current operating point is to the left of the maximum power point, the voltage needs to be increased and the reference voltage needs to be updated; otherwise, if the current operating point is to the right of the maximum power point, the voltage needs to be decreased and the reference voltage needs to be updated; S5. Repeat steps S2 to S4 until the MES operating point reaches the maximum power point.

10. The high-frequency pulsation active energy harvesting microbial electrochemical method based on PID control according to claim 9 is characterized in that: The method for updating the reference voltage is: Among them, V ref (k) is the updated reference voltage, V ref (k-1) is the reference voltage of the previous cycle, K pi Different proportional coefficients are introduced according to the symbols to achieve adaptive adjustment of step size.

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