Fuel cell output control circuit, unit and control system

Abstract

The utility model provides a fuel cell output control circuit, unit and control system, and relates to the technical field of fuel cell management, comprising: a conversion circuit, the input side of which is connected with a single-chip microcomputer to obtain a PWM signal output by the single-chip microcomputer and generate a reference voltage signal; the input side of the comparison circuit is connected with the fuel cell and the conversion circuit, the output side of the comparison circuit is connected with the power supply module, and the comparison circuit receives the current output signal of the electric pile and the reference voltage signal, compares the current output signal and the reference voltage signal and outputs a control signal to the power supply module so as to adjust the output voltage of the fuel cell. And the control effect is not good enough.

Description

TECHNICAL FIELD

[0001] The utility model relates to fuel cell management technical field especially relates to a kind of fuel cell control output circuit, unit and control system. BACKGROUND

[0002] Fuel cell is a kind of efficient, clean power generation device, and the chemical energy of fuel (such as hydrogen) and oxidant (such as oxygen) is directly converted into electric energy by electrochemical reaction.

[0003] Fuel cell is widely used in transportation, distributed power generation and portable power supply and other fields. The stability and controllability of fuel cell output power directly affect the expansion of its application scenarios and the overall performance of the system, therefore, designing efficient and reliable output control hardware circuit becomes the key link to improve the performance of fuel cell system.

[0004] The control strategy part of the existing most applications is realized by complex circuit, or such as open-loop control strategy, and the expected output value is set to run program to output instruction, and most of the design structure is complex, which may cause long response delay, unable to accurately and quickly control and other problems, so that the control effect is not good enough, and cannot meet the application of part of scene. UTILITY MODEL CONTENT

[0005] In order to overcome the above technical defects, the purpose of the utility model is to provide a kind of fuel cell output control circuit, unit and control system, solve the problem of complex structure of existing fuel cell output control, and the control effect is not good enough.

[0006] The utility model discloses a kind of fuel cell output control circuit, comprising:

[0007] Conversion circuit, input side connection single-chip microcontroller, obtains the PWM signal output by single-chip microcontroller and generates reference voltage signal;

[0008] Comparison circuit, input side connection fuel cell with the conversion circuit, output side connection power module, receives the current output signal of electric pile and reference voltage signal, and after comparison, output control signal to power module, so as to adjust the output voltage of fuel cell.

[0009] Preferably, the conversion circuit includes at least one filter.

[0010] Preferably, the conversion circuit further includes MOS device and follower;

[0011] The input end of the MOS device is connected to the input side of the conversion circuit and receives the PWM signal.

[0012] The output end of the MOS device is connected to the input end of the follower through the filter, and the output end of the follower is connected to the comparison circuit.

[0013] Preferably, the comparison circuit includes a comparator;

[0014] The comparator receives the current output signal from the fuel cell at its positive input terminal, receives the reference voltage signal at its negative input terminal, and its output terminal is connected to the pin of the power module to control the output power of the power module.

[0015] Preferably, the negative input terminal of the comparator is connected to its output terminal via a capacitor.

[0016] Preferably, a sampling resistor is connected to the positive input terminal of the comparator.

[0017] This utility model provides a fuel cell output control unit.

[0018] It includes a microcontroller and a power supply module; it also includes the fuel cell output adjustment circuit described in any of the above items.

[0019] Preferably, the microcontroller is configured to output PWM signals according to a predetermined rule.

[0020] Preferably, the microcontroller is configured to dynamically control the output PWM signal according to the output voltage of the fuel cell, thereby dynamically adjusting the output power of the power module.

[0021] This utility model also provides a fuel cell control system, including the fuel cell output control unit described in any of the above claims.

[0022] Compared with existing technologies, the above technical solution has the following advantages:

[0023] 1. The fuel cell output control circuit provided in this application converts the PWM signal output by the microcontroller into a reference voltage signal through a conversion circuit, compares it with the actual output current signal of the fuel cell stack, and thus dynamically adjusts the power output of the power module. This hardware control solves the problems of complex output control of existing fuel cells, which may result in response delay and poor control effect.

[0024] 2. The control unit using this control circuit can precisely adjust the comparator's reference voltage signal through a microcontroller, so that the fuel cell stack gradually increases its output power until it reaches full power operation.

[0025] 3. The control unit using this control circuit can preset or adjust the reference voltage signal through a microcontroller, thereby monitoring the voltage status of the fuel cell stack in real time. When the output voltage is lower than the preset protection threshold, it can respond quickly and limit the output power of the fuel cell stack, reducing the damage to the fuel cell stack caused by excessively low / high voltage. It can also achieve dynamic adjustment, so that the fuel cell always operates within a safe range, improving the output stability and safety of the fuel cell. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The circuit diagram of the fuel cell output control circuit, unit and control system embodiment is described in the utility model.

[0027] Reference Signs:

[0028] 1 - single-chip microcomputer;2 - power module. DETAILED DESCRIPTION

[0029] The advantages of the utility model will be further described below in combination with the drawings and specific embodiments.

[0030] The exemplary embodiments will be described in detail hereinbelow with reference to the accompanying drawings. In the following description, the same numbers in different drawings represent the same or similar elements unless otherwise represented. The embodiments described in the following exemplary embodiments are not representative of all embodiments consistent with the present disclosure. Rather, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0031] The terms used in the present disclosure are merely for the purpose of describing specific embodiments and are not intended to limit the present disclosure. The singular forms "a", "an" and "the" used in the present disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein means and includes any or all possible combinations of one or more associated listed items.

[0032] In the description of the utility model, it should be understood that the orientations or positional relationships indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like are based on the orientations or positional relationships shown in the drawings, and are merely for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the utility model.

[0033] In the description of the utility model, unless otherwise specified and limited, it should be noted that the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be mechanical connection or electrical connection, or the communication between two elements, or direct connection, or indirect connection through intermediate medium, and those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0034] In the following description, the suffix such as "module", "component" or "unit" used for representing an element is only for the convenience of the description of the present application, and has no specific meaning by itself. Therefore, "module" and "component" can be used interchangeably.

[0035] Embodiment one: the embodiment provides a fuel cell output control circuit, which realizes control of fuel cell output voltage through arrangement of pure hardware circuit, specifically comprising:

[0036] A conversion circuit is connected to the input side of the single-chip microcomputer, acquires the PWM signal output by the single-chip microcomputer, and generates a reference voltage signal;

[0037] A comparison circuit is connected to the fuel cell and the conversion circuit at the input side, and is connected to the power module at the output side, receives the current output signal of the fuel cell stack and the reference voltage signal, and outputs a control signal to the power module after comparison, so as to adjust the output voltage of the fuel cell.

[0038] In the present embodiment, through the circuit arrangement of pure hardware (formed by passive elements such as resistors (R), capacitors (C), inductors (L) or active elements such as operational amplifiers), the comparison circuit converts the PWM signal into a reference voltage signal, and compares the current output signal of the fuel cell stack (i.e. the actual output of the fuel cell) to control the output power of the power module, so as to realize the output control of the fuel cell, without instruction analysis, with fast control speed, dynamic adjustment of the actual output of the fuel cell realized by the single-chip microcomputer, high control precision and good control effect.

[0039] Specifically, the hardware arrangement of the conversion circuit is as follows:

[0040] The conversion circuit comprises at least one filter, which can be an RC filter, an LC filter or a filter formed by integrated operation, sampling, etc. The filter converts the PWM signal into a stable voltage (reference voltage signal). In the present embodiment, an RC filter is arranged. The filter can be arranged in multiple, same type or different type, in series or in parallel, and is selectively arranged according to the actual scene. As shown in the circuit, two RC filters are connected in series (to realize second-order filtering).

[0041] Further, the conversion circuit integrates MOS devices and followers, which cooperate with the RC filter to amplify, impedance match and buffer the signal. Specifically, the input end of the MOS device is connected to the input side of the conversion circuit to receive the PWM signal. The output end of the MOS device is connected to the input end of the follower through the filter, and the output end of the follower is connected to the comparison circuit.

[0042] The aforementioned MOS device can be either an NMOS transistor or a PMOS transistor. In this embodiment, the PWM signal is input from the gate, grounded at the source, and connected to the input of the RC filter at the drain. It is then connected to the positive terminal of the follower input through two RC filters and output from the follower output to the comparator circuit.

[0043] Specifically, as an example, the microcontroller (with one pin connected to the gate of the MOS device) outputs a PWM control wave, which is then processed by an RC filter or a second-order RC filter to convert it into a stable voltage signal. This voltage value is then fed into a follower (circuit) to ensure the stability and accuracy of the signal (outputting a reference voltage signal), and is finally passed to the comparator in the comparison circuit.

[0044] Specifically, the hardware layout of the comparator circuit is as follows:

[0045] The comparison circuit includes a comparator; the positive input terminal of the comparator receives the current output signal of the fuel cell, the negative input terminal receives the reference voltage signal, and the output terminal is connected to the pin of the power module to control the output power of the power module.

[0046] In this embodiment, based on the example above, the reference voltage signal is input to the negative input terminal of the comparator. The other end (positive input terminal) of the comparator is connected to the current value of the current-limited output, i.e., the voltage-converted form of the actual output current of the fuel cell stack. Specifically, as shown in the circuit diagram, a sampling resistor is connected to the positive input terminal of the comparator to convert the current signal output by the fuel cell into a voltage signal for comparison and switching by the comparator. Optionally, a resistor can also be connected to the negative input terminal of the comparator for further filtering or sampling.

[0047] In this embodiment, the negative input terminal of the comparator is connected to its output terminal via a capacitor. This arrangement forms a specific structure where changes in the comparator's output level affect the voltage at the negative input terminal via the capacitor. For example, if the output terminal is high, the capacitor begins to charge, causing the voltage at the negative input terminal to gradually rise; when the output terminal becomes low, the capacitor discharges through some means, causing the voltage at the negative input terminal to drop. This achieves hysteresis comparison, introducing positive feedback and a delay mechanism.

[0048] Therefore, a comparison is formed between the voltage value adjusted by the microcontroller (the reference voltage signal, used as a comparison value) and the output current value of the fuel cell stack (the output current signal). When the current value exceeds the preset comparison value, the comparator output will flip, generating a signal. This signal is then used to adjust the power supply output as feedback to achieve current limiting and power limiting output, thereby ensuring that the fuel cell stack can gradually increase its output power at a limited power during the startup phase.

[0049] Based on the above fuel cell output control circuit, the slow power rising process required for the start of the fuel cell can be realized. As shown in the figure, the single-chip microcomputer outputs a PWM signal (which can be set to increase slowly) to the MOS tube to adjust the reference voltage value output. After RC filtering, a stable voltage output is reached. The follower increases the output impedance to one end of the comparator. The other end of the comparator is the detected current value of the fuel cell stack. At this time, if the PWM output of the single-chip microcomputer is adjusted, the output of the comparator will be adjusted accordingly. The comparator can act on the feedback pin of the DC-DC module (power module), thereby adjusting the power output of the DC-DC module accordingly. Thus, the fuel cell voltage output can be dynamically adjusted according to the characteristics of the fuel cell, ensuring that the fuel cell can operate stably under different working conditions.

[0050] In the present embodiment, the PWM signal output by the single-chip microcomputer is converted to generate a reference voltage signal as the comparison value of the output current of the stack. The comparator realizes pure hardware control of the fuel cell output voltage, which is fast and precise.

[0051] It can be understood that the comparison of the reference voltage signal and the current signal output by the stack can realize dynamic control of the fuel cell output voltage, so that the fuel cell can operate stably under different working conditions. In the application of hydrogen energy assisted vehicles, the load condition is combined to adjust the fuel cell output power through the control circuit, realizing precise and rapid control.

[0052] Embodiment two: The present embodiment can provide a fuel cell output control unit, comprising a single-chip microcomputer and a power module; further comprising the fuel cell output adjustment circuit described in embodiment one.

[0053] As described in embodiment one, the PWM signal output by the single-chip microcomputer can be pre-configured or dynamically adjusted.

[0054] Specifically, in a preferred embodiment, the single-chip microcomputer is configured to output a PWM signal according to a predetermined rule to realize dynamic output of the fuel cell. As an example, the slow start process of the fuel cell can be realized.

[0055] The slow start process of the fuel cell stack adjusts the reference voltage value of the comparator (reference voltage signal) through the output of the single chip microcomputer (PWM signal). In the initial stage (e.g. time as a control dimension, initial stage t=0), the reference voltage value can be set to a small value. Once started, the output of the power module will be adjusted accordingly through the comparison of the comparator to ensure that its output power is limited within the preset range. After a predetermined period (time t=predefined value), or the current signal of the stack output reaches a predetermined current value, or the comparator no longer flips, the output of the single chip microcomputer (PWM signal) can gradually change to adjust the reference voltage signal to gradually increase until the stack reaches the predetermined full power operating state. By this step-by-step increasing output control method, the fuel cell stack is protected from damage, giving a suitable power output rise curve.

[0056] Based on the above, by precisely adjusting the reference voltage value of the comparator through the single chip microcomputer, the stack is operated at a small power in the early stage of startup, the output power is gradually increased, and the full power operating state is reached. This process effectively reduces the damage to the stack due to sudden loading and prolongs the service life of the stack.

[0057] It can be understood that setting a constant output PWM signal is also an optional setting, which is applied in different scenarios compared to the above dynamic process.

[0058] Further in another preferred embodiment, the single chip microcomputer is configured to dynamically control the output PWM signal according to the output voltage of the fuel cell, thereby dynamically adjusting the output power of the power module.

[0059] After the above slow start process, the fuel cell enters the working state (full power operating state), and in this process, the output voltage of the fuel cell can also be kept within a certain range / threshold (upper / lower) by setting the PWM signal output by the single chip microcomputer according to the output voltage of the fuel cell. Once it exceeds (i.e. there may be a safety risk), it will be dynamically adjusted, which can quickly realize the function similar to under-voltage or over-voltage protection.

[0060] Specifically, as an example, the protection threshold of the stack is determined by the PWM signal output by the single-chip microcomputer (the adjustment / determination of the protection threshold can be realized by adjusting the PWM signal), so that a dynamic comparison relationship is always maintained between the reference voltage signal output by the single-chip microcomputer and the actual voltage value of the stack (the output voltage of the fuel cell). Thus, the output voltage of the fuel cell (i.e., whether it is above the under-voltage protection threshold) can be monitored in real time, and intervention can be performed as necessary, such as when the output voltage of the fuel cell is lower than the protection threshold, the PWM signal is adjusted to cause the comparator to flip, increasing the output power of the power supply module, and the over-voltage function is similar, the protection threshold under the preset high voltage is flipped to reduce the output power of the power supply module, thereby realizing the hardware limitation of the high voltage or low voltage of the stack, and ensuring that the fuel cell operates within a safe range. The protection function of the stack can be realized by the above-mentioned application hardware, which can react more quickly, protect quickly, and shorten the response time.

[0061] By adjusting the PWM signal in real time, the reference voltage signal is dynamically adjusted, and the circuit can ensure that the fuel cell operates within a safe range. When an abnormal output voltage or output current value is detected, the output power of the power supply module can be adjusted or protective measures can be taken in time, thereby improving the stability and safety of the entire system.

[0062] As an illustration, the degradation of a fuel cell (such as hydrogen) is the result of the combined action of material aging and operating conditions, and activation is an effective way to solve it. However, the degradation in the engineering field is a slow process, and the stack often needs to continue to work before the degradation amount reaches the activation standard, so the protection parameters of the stack voltage after degradation (i.e., the above-mentioned protection threshold) also need to be adjusted accordingly. Similarly, using the above-mentioned control circuit can adjust the output of the stack and the protection range in time, prolonging the actual engineering application time of the stack and the protection effect.

[0063] Based on the above, considering the degradation problem of the (hydrogen) fuel cell, the protection threshold range of the stack voltage can be dynamically adjusted. For example, considering the aging and degradation of the stack (change with time or output voltage), the PWM signal output by the single-chip microcomputer is automatically adjusted to adjust the above-mentioned protection threshold, ensuring that the stack can still operate safely and stably after degradation, and prolonging the service life of the stack.

[0064] The embodiment also provides a fuel cell control system, which comprises the above-mentioned fuel cell output control unit and is applied to the fields of power supply, transportation, new energy, etc. The fuel cell system can also be connected or integrated with other control modules / systems to realize application in different application scenarios.

[0065] The above-mentioned embodiments one and two respectively embody the application of hardware circuit and the adjustment of reference voltage signal realized by integrated single-chip microcomputer, so that different functions are realized, and are respectively or simultaneously applied in different scenes, which is not limited, and fuel cell output voltage can be quickly and accurately controlled by a hardware mode.

[0066] It should be noted that the embodiments of the present application have good implementation, and are not limited in any form to the present application. Any skilled person in the art can change or modify the equivalent effective embodiments by using the disclosed technical content, as long as it does not deviate from the technical solution of the present application, and any modification or equivalent change and modification of the above embodiments according to the technical essence of the present application still belongs to the scope of the technical solution of the present application.

Claims

1. A fuel cell output control circuit, characterized in that... ,include: The conversion circuit connects to a microcontroller on the input side, acquires the PWM signal output by the microcontroller, and generates a reference voltage signal. The comparator circuit has its input side connected to the fuel cell and the conversion circuit, and its output side connected to the power module. It receives the current output signal of the fuel cell stack and the reference voltage signal, compares them, and outputs a control signal to the power module to adjust the output voltage of the fuel cell.

2. The fuel cell output control circuit according to claim 1, characterized in that... : The conversion circuit includes at least one filter.

3. The fuel cell output control circuit according to claim 2, characterized in that... : The conversion circuit also includes MOS devices and followers; The input terminal of the MOS device serves as the input side of the conversion circuit, receiving the PWM signal. The output terminal of the MOS device is connected to the input terminal of the follower through the filter, and the output terminal of the follower is connected to the comparator circuit.

4. The fuel cell output control circuit according to claim 1, characterized in that... : The comparison circuit includes a comparator; The comparator receives the current output signal from the fuel cell at its positive input terminal, receives the reference voltage signal at its negative input terminal, and its output terminal is connected to the pin of the power module to control the output power of the power module.

5. The fuel cell output control circuit according to claim 4, characterized in that... : The negative input terminal of the comparator is connected to its output terminal via a capacitor.

6. The fuel cell output control circuit according to claim 4, characterized in that... : A sampling resistor is connected to the positive input terminal of the comparator.

7. A fuel cell output control unit, characterized in that... : Includes microcontrollers and power modules; It also includes the fuel cell output adjustment circuit according to any one of claims 1-6.

8. The fuel cell output control unit according to claim 7, characterized in that... : The microcontroller is configured to output PWM signals according to a predetermined rule.

9. The fuel cell output control unit according to claim 8, characterized in that... : The microcontroller is configured to dynamically control the output PWM signal based on the output voltage of the fuel cell, thereby dynamically adjusting the output power of the power module.

10. A fuel cell control system, characterized in that... The fuel cell output control unit includes any one of claims 7-9 above.

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