A hierarchical control system for a DMFC system and its control method

Abstract

The present invention provides a hierarchical control system for a DMFC system and its control method, which can minimize the differences between systems and maximize the parallel usage effect throughout the entire life cycle of the product, and can support the cascading of multiple systems, refine the power supply gradient, and provide more possibilities for load matching. The technical solution is as follows: A hierarchical control system for a DMFC system, which includes a cascading controller. The cascading controller includes an MCU unit, an environmental sensor, a fuel sensor, a remote communication module, a positioning module, a power supply unit, and an interface. The interface is connected to a bus interface, and a plurality of branch interfaces are provided on the bus interface, and the branch interfaces are respectively connected to the DMFC systems.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, in particular to a cascade control system and a control method for a DMFC system. Background Art

[0002] In the field of off-grid power supply, the current mainstream solutions are to use power generation methods such as solar energy and wind energy, and power-matched solar panels or wind power generation systems can be configured according to the load size. In areas such as plateaus and high-cold regions with long-term snow cover, fuel cells are also used as backup power supply solutions, especially direct methanol fuel cells (DMFCs). Users can also configure DMFC products with different powers according to different load power consumption situations. However, for a few larger-power loads, there is no matching DMFC system. Developing a targeted fuel cell system may incur higher costs, but it is possible to supply power to them by using multiple fuel cell systems in parallel. The solution for parallel power supply of DMFC only requires designing a cascade controller to achieve reasonable distribution and intelligent regulation of the system power generation, thereby increasing the coverage range of the load power and reducing the R & D cost.

[0003] Existing similar solutions only perform current sharing output control between systems, which can achieve average power distribution among parallel systems. To a certain extent, it can ensure the balanced operation of each system and the parallel use effect when the performance differences between systems are very small. However, since this device can only achieve current sharing control and does not have the functions of detecting the states of each system and making each system work synchronously, as time goes by, the performance differences between systems gradually increase, and this device will exacerbate the differences between systems and can no longer effectively ensure the parallel use effect. Summary of the Invention

[0004] In view of the above technical problems, the present invention provides a cascade control system for a DMFC system, which can minimize the differences between systems and maximize the parallel use effect throughout the entire life cycle of the product, and can support the cascade of multiple systems, refine the power supply gradient, and provide more possibilities for load matching. The present invention also provides a control method for the cascade control system of the DMFC system.

[0005] Its technical solution is as follows: A cascade control system for a DMFC system, characterized in that it includes a cascade controller, and the cascade controller includes an MCU unit, an environmental sensor, a fuel sensor, a remote communication module, a positioning module, a power supply unit, and an interface. The interface is connected to a bus interface, and a plurality of branch interfaces are provided on the bus interface, and the branch interfaces are respectively connected to DMFC systems.

[0006] It is further characterized in that the MCU unit is used for comprehensively processing the information and control algorithms of each unit; the environmental sensor is used for collecting the surrounding environmental information of the cascade system, the fuel sensor is used for detecting the remaining fuel amount of the fuel cell system, the positioning module is used for obtaining the position information of the system to facilitate remote positioning, the remote communication module is used for remote information transmission between the user and the system, and the system sends relevant information of the system to the user through this module. The power supply unit obtains power from the bus and supplies power to each module after level conversion. The interface is mainly used for communication between the cascade controller and the bus interface to obtain the status information of each system or issue commands, and obtains power from the bus interface. Each system can be connected to the bus through the interface on the bus interface to communicate with the cascade controller and provide power to the cascade controller. The interface usually adopts common interface levels or interface protocols, such as RS485, RS232; I2C, CAN bus.

[0007] A control method for a cascade control system of a DMFC system, which includes the following steps:

[0008] 1. The cascade controller obtains environmental information;

[0009] 2. The cascade controller calculates the theoretical operating condition parameters of the system;

[0010] 3. The cascade controller obtains the working state information and fault alarm information of each system;

[0011] 4. The cascade controller determines the startup state of the working system. If a system starts, it then determines whether it is started in the anti-freezing mode. If a system does not start, it re-enters step 1;

[0012] 5. If it is started in the anti-freezing mode in step 4, the system is kept working normally. If there is no anti-freezing mode start in step 4, the remaining systems are awakened and the anti-freezing mode start is forcibly converted to the normal mode start;

[0013] 6. Keep each system in step 5 working normally;

[0014] 7. When the cascade controller detects that at least one system stops working due to the completion of load charging, it will immediately stop the work of all systems and all enter the standby state; when the cascade controller detects that a certain system stops working due to a fault, the remaining systems will continue to operate normally until the power supply of the load is effectively replenished, that is, the charging is completed.

[0015] It is further characterized in that it also includes a remote communication control method, which includes the following steps:

[0016] 1. The cascade controller obtains environmental sensor information;

[0017] 2. The cascade controller obtains fuel sensor information;

[0018] 3. The cascaded controller acquires the operating status information and fault alarm information of each system.

[0019] 4. The cascaded controller acquires location information.

[0020] 5. Decode the information and transmit it to the user.

[0021] With the above structure, the present invention has a cascaded controller including an MCU unit, an environmental sensor, a fuel sensor, a remote communication module, a positioning module, a power supply unit, and an interface. The interface is connected to a bus interface, and multiple branch interfaces are provided on the bus interface. The branch interfaces are respectively connected to DMFC systems. Starting from both the equal current sharing control and the system status synchronization control, the problem is fundamentally solved. It can minimize the differences between systems and maximize the parallel usage effect throughout the entire life cycle of the product, and can support the cascading of multiple systems, refine the power supply gradient, and provide more possibilities for load matching. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic diagram of the cascaded control system of the present invention;

[0023] Figure 2 is a schematic diagram of the cascaded control process;

[0024] Figure 3 is a schematic diagram of the remote communication process. DETAILED DESCRIPTION OF THE INVENTION

[0025] The present invention will be further described below in conjunction with the drawings and embodiments.

[0026] See Figure 1 , a cascaded control system for a DMFC system, which includes a cascaded controller. The cascaded controller includes an MCU unit, an environmental sensor, a fuel sensor, a remote communication module, a positioning module, a power supply unit, and an interface. The interface is connected to a bus interface, and multiple branch interfaces are provided on the bus interface. The branch interfaces are respectively connected to DMFC systems.

[0027] The MCU unit is used to comprehensively process the information and control algorithms of each unit. The environmental sensor is used to collect the surrounding environmental information of the cascade system. The fuel sensor is used to detect the remaining fuel quantity of the fuel cell system. The positioning module is used to obtain the position information of the system for convenient remote positioning. The remote communication module is used for remote information transmission between the user and the system. The system sends relevant information of the system to the user through this module. The power supply unit obtains power from the bus and supplies power to each module after level conversion. The interface is mainly used for communication between the cascade controller and the bus interface to obtain the status information of each system or issue instructions, and obtains power from the bus interface. Each system can be connected to the bus through the interface on the bus interface to communicate with the cascade controller and provide power to the cascade controller. The interface usually adopts common interface levels or interface protocols, such as RS485, RS232, I2C, and CAN bus.

[0028] See Figure 2 , the present invention also includes a control method for the cascade control system of a DMFC system, which includes the following steps:

[0029] Step 1: The cascade controller obtains environmental information;

[0030] Step 2: The cascade controller calculates the theoretical operating condition parameters of the system;

[0031] Step 3: The cascade controller obtains the working state information and fault alarm information of each system;

[0032] Step 4: The cascade controller determines the startup state of the working system. If a system starts up, it then determines whether it is started in the anti-freezing mode. If a system does not start up, it then re-enters Step 1;

[0033] Step 5: If it is started in the anti-freezing mode in Step 4, keep the system working normally. If there is no anti-freezing mode startup in Step 4, wake up the remaining systems and force the anti-freezing mode startup to be converted to the normal mode startup. Step 6: Keep the systems in Step 5 working normally;

[0034] Step 7: When the cascade controller detects that at least one system stops working due to the completion of load charging, it will immediately stop the work of all systems and all enter the standby state. When the cascade controller detects that a certain system stops working due to a fault, the remaining systems will continue to operate normally until the power supply of the load is effectively replenished, that is, the charging is completed.

[0035] The reasons for system startup are divided into normal power generation startup and antifreeze mode startup. If there is no antifreeze mode startup, it means it is due to normal power generation mode startup. As long as the cascade controller senses that one system is started due to the power generation mode, it will send commands to other systems to wake them up and enter the power generation working mode. At the same time, the system that is in the antifreeze mode will be forced to convert to the power generation mode. In this way, each system can achieve synchronous power generation, and then cooperate with the software algorithm to intelligently control the system and reasonably distribute the power generation power, ultimately achieving the purpose of minimizing the differences between systems and maximizing the parallel usage effect throughout the entire life cycle of the product.

[0036] The cascade controller determines whether to perform synchronous control and current sharing output control by detecting the operating states of each parallel system.

[0037] In a low-temperature environment, the system will enter the antifreeze mode, which aims to heat itself through the heat generated by the reaction to play a protective role and prevent component damage, while external power generation becomes a secondary factor.

[0038] If it is detected that a certain system starts due to excessive load power feeding, the cascade controller will wake up all other systems and force the system operating in the antifreeze mode to switch to the normal working mode to achieve the maximum power generation. Before startup, the cascade controller will also collect data on the surrounding environment, calculate the operating condition parameters suitable for the system to work, optimize the control of the internal components of the system, improve the fuel utilization rate of the system, and at the same time perform current sharing control on each system to reduce the consistency differences between each system. Reducing the consistency differences between systems can effectively extend the service life of the parallel system and further maximize the power generation effect.

[0039] When a certain system shuts down due to a fault, the remaining systems will continue to operate normally until the power feeding of the load is effectively replenished (i.e., the charging is completed).

[0040] When the cascade controller detects that at least one system shuts down due to the completion of load charging, it will immediately stop the operation of all systems and all enter the standby state to prevent the situation where some systems shut down while some continue to operate due to detection differences. This situation will cause the differences between systems to become larger and larger. In the long run, some systems will have their service lives exhausted while some systems have less service life usage, and the power generation effect cannot be maximized.

[0041] See Figure 3 , a control method for the cascade control system of a DMFC system also includes a remote communication control method, which includes the following steps:

[0042] Step 1: The cascade controller obtains environmental sensor information;

[0043] Step 2: The cascade controller obtains fuel sensor information;

[0044] Step 3: The cascade controller obtains the working status information and fault alarm information of each system;

[0045] Step 4: The cascade controller obtains the position information;

[0046] Step 5: Decode the information and transmit it to the user.

[0047] The remote communication function can send the status information and position information of the system to the user terminal in real time, facilitating the user to monitor the system operation status and load power supply situation, and can also send commands to the cascade controller to achieve remote control of the system.

[0048] Both the current sharing control and the system state control are achieved through the control of the MCU. The modules in the cascade control mainly implement the surrounding environment monitoring, remote communication, and communication with the system. After obtaining the data of the surrounding environment, the status information of the system, the instructions of the user, etc., the cascade controller comprehensively processes them through algorithms and finally transmits commands to each system. Each system makes corresponding adjustments according to the received commands, that is, realizes the state control and current sharing power generation control of each system. Each system already contains the basic hardware circuits for current control and communication, but the realization of the current sharing control and state control between each system is the result of the processing in the cascade controller.

[0049] The above schematically describes the present invention and its implementation manners. This description is not restrictive. What is shown in the drawings is only one of the implementation manners of the present invention. The actual structure is not limited thereto. Those of ordinary skill in the art are inspired by it and, without departing from the creative purpose, design similar structural manners and embodiments to this technical solution without creative efforts, which should all fall within the protection scope of the present invention.

Claims

1. A control method for a cascade control system of a DMFC system. The cascade control system includes a cascade controller, and the cascade controller includes an MCU unit, an environmental sensor, a fuel sensor, a remote communication module, a positioning module, a power supply unit, and an interface. The interface is connected to a bus interface, and a plurality of branch interfaces are provided on the bus interface, and the branch interfaces are respectively connected to the DMFC systems. The cascade control method includes the following steps: Step 1: The cascade controller obtains environmental information; Step 2: The cascade controller calculates the theoretical operating condition parameters of the DMFC system; Step 3: The cascade controller obtains the working state information and fault alarm information of each DMFC system; Step 4: The cascade controller determines the startup state of the working DMFC system. If a system starts up, then it further determines whether all are started in the anti-freezing mode. If a system does not start up, then it re-enters Step 1; Step 5: If all are started in the anti-freezing mode in Step 4, then keep the DMFC system working normally. If at least one system in Step 4 is not started in the anti-freezing mode, then wake up the remaining systems and force the startup mode conversion from the anti-freezing mode to the normal mode; Step 6: Keep the normal operation of each DMFC system in Step 5; Step 7: When the cascade controller detects that at least one DMFC system stops operating due to the completion of load charging, it will immediately stop the operation of all DMFC systems and all enter the standby state; when the cascade controller detects that a certain system stops operating due to a fault, the remaining DMFC systems will continue to maintain the normal operation state until the power supply of the load is effectively replenished, that is, the charging is completed.

2. A control method for a cascade control system of a DMFC system according to claim 1, which further includes a remote communication control method, and it includes the following steps: Step 1: The cascade controller obtains environmental sensor information; Step 2: The cascade controller obtains fuel sensor information; Step 3: The cascade controller obtains the working state information and fault alarm information of each DMFC system; Step 4: The cascade controller obtains location information; Step 5: Decode the information and transmit it to the user.

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